Unit 5 Revealing nature
Ⅰ.阅读理解(每题2.5分,共30分)
A
Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night.This solves the problem of how to portion out (分配) energy reserves during the night so that the plant can keep growing,yet not risk burning off all its stored energy.
While the sun shines,plants perform photosynthesis (光合作用).In this process,the plants change sunlight,water and carbon dioxide into stored energy in the form of long chains of sugar,called starch (淀粉).At night,the plants burn this stored starch to fuel continued growth.
“The calculations are precise so that plants not only prevent starvation but also make the most efficient use of their food,” said study co-author Alison Smith.“If the starch store is used too fast,plants will starve and stop growing during the night.If the store is used too slowly,some of it will be wasted.”
The scientists studied the plant Arabidopsis (拟南芥),which is regarded as a model plant for experiments.To give the plants some math tests,the biologists let night arrive unexpectedly early or late for them.
During one of the exams,they shut off the lights early on plants that had been grown with twelve-hour days and nights.Putting them into darkness after only an eight-hour day meant they didn’t have time to store as much starch as usual.And this forced the plants to adjust their normal night rhythm.
Amazingly,even after this day length trick,the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night.They had neither starved,nor stored starch that could have been used to fuel more growth.
The authors suggested that similar biological calculators may explain how a migratory bird,the little stint (滨鹬),can make a five-thousand-kilometre journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more,on average.
( )1.According to the passage,plants .
[A] use little energy during the day
[B] usually stop growing at night
[C] waste a lot of energy at night
[D] store starch during the day
( )2.What did the scientists do when studying Arabidopsis
[A] They changed the plants’ light conditions.
[B] They provided the plants with more starch.
[C] They tried to keep the plants’ natural rhythm.
[D] They attached a biological calculator to the plants.
( )3.When morning arrived,the experimental plants .
[A] nearly died of lack of food
[B] used most of their stored energy
[C] began to regulate their food store
[D] stored enough starch for the next day
( )4.The passage mainly tells us .
[A] plants feel hungrier day by day
[B] plants are good at storing energy
[C] plants do math to survive the night
[D] plants use starch to fuel their growth
B
The colour blue is very rare in nature,with fewer than one in ten plants sporting the colour universally favoured by humans.To present this colour,they have to perform tricks to make themselves blue to the human eyes.In some flowers like bluebells,it primarily occurs when naturally occurring pigments (色素) are mixed the way you can mix different paints to change the colour.
For blueberries,the blue colour comes from the naturally produced thin layer of wax (蜡) on their skin,which often serves as a self-cleaning coating or for added protection in the plant kingdom.“The blue colour of most fruits is in their pigmented juices.That isn’t the case with blueberries,” says Rox Middleton,co-author of a study published in a scientific journal.
In the study,Middleton and his team examined the wax of a blueberry using an electron microscope.They found that the layer of wax is composed of tiny structures that work by scattering (散射) blue and UV light from the sun,while absorbing most of other colours of light.The arrangement makes the berries appear blue to humans and blue-UV to birds and other species that can see UV light,despite not having blue pigments in the waxy skin itself.
To look closer,they removed the outer wax and reshaped it on a black card.They created a new blue-UV coating and removed a very thin substance that creates colour called a colorant from the skin.“The colorants scatter blue and UV,letting the other colours pass through without absorption,” says Middleton.“That’s why it’s so important that there are dark pigments underneath to ‘mop up’ the rest of the light.If there was a bright pigment or white scattering material underneath,that light would come through,and the colour would look mixed or washed out.”
The study does show that nature has developed a “really neat trick” in the form of a very thin layer for an important colorant.Reproducing this colorant in the lab could make a way for new methods of creating pigments.
( )5.How do bluebells present blue to humans
[A] By blocking natural light.
[B] By combining the pigments.
[C] By changing the outer colour.
[D] By producing various paints.
( )6.What did Middleton’s team discover about the wax layer on blueberries
[A] Its colourful pigments.
[B] Its internal mechanism.
[C] Its chemical changes.
[D] Its unique components.
( )7.Which of the following can replace the underlined phrase “mop up” in Paragraph 4
[A] Mix. [B] Reflect.
[C] Recognise. [D] Absorb.
( )8.What is a suitable title for the text
[A] The Science Behind Plant Colours
[B] The Invisible Pigments of Blueberries
[C] Technically,Blueberries Aren’t Blue
[D] Indeed,Colour Blue Is Humans’ Favourite
C
Every August the clustered carline thistle (蓟) is one of the plants that flower in most of Spain’s dry Mediterranean habitats,making it a dominant plant for the local bees and other pollinators.But how can the thistle survive,much less flower,when its neighbours are reduced to twigs and dust
Spanish National Research Council evolutionary ecologist Herrera had an amazing discovery when one day he peered into a thistle blossom to see how much nectar was inside and lightly touched the flower.He discovered that even after hours in direct sun,the flower heads were routinely five degrees cooler than their surroundings during the heat of the day,with the difference approaching 10 degrees for some flowers on the hottest days.
Sanna Sevanto,a physicist and plant physiologist,says that Herrera’s finding is exciting and could confirm a risky plant survival strategy that has,until now,only been theorised.
Sevanto and other scientists have documented that to perform photosynthesis (光合作用),leaves need access to carbon dioxide,which enters through tiny pores (细孔) called stomata on the leaf’s surface.When stomata open to let carbon dioxide in,some water escapes; this causes evaporative cooling that lowers the leaf’s temperature slightly.
But for the Spanish thistle,evaporative cooling could be the goal rather than just a side effect of photosynthesis.Herrera suggests the plant could essentially be sweating: sacrificing precious water,so scarce in Spain’s dry summers,to prevent its delicate reproductive organs from overheating.He adds that some flower species have stomata on their petals,which Sevanto says would be an easy route for releasing water.Opening stomata in a drought is a big gamble,though,and he notes that,so far,“we have not observed a plant that would do it to cool themselves.”
As heat waves become more frequent and intense with climate change,it’s increasingly important to study unusual adaptations that help plants survive heat stress.But ultimately,“whether these plants will have water enough to keep the system working,” Herrera says,“that’s another story.”
( )9.What was Herrera’s discovery about carline thistle in during the hottest days
[A] It was the only plant that blossomed.
[B] It was the only plant that survived.
[C] It had little nectar in the flower.
[D] It had lower temperature in the flower head.
( )10.Why does carline thistle open stomata in hot weather
[A] To cool the key organs.
[B] To take in carbon dioxide.
[C] To accelerate photosynthesis.
[D] To reduce water content in leaves.
( )11.What does the underlined word “gamble” in Paragraph 5 refer to
[A] Advantage. [B] Risk.
[C] Shift. [D] Evolution.
( )12.What is Herrera’s attitude towards the plants’ way to adapt to heat stress
[A] Suspicious. [B] Positive.
[C] Objective. [D] Unconcerned.
Ⅱ.完形填空(每题1分,共15分)
I recall as a young child bringing a bunch of brilliant flowers to my mother.She was amazed at its shape but her passion eventually 1 .Both my parents hated the 2 of these flowers in the lawn.
There were an ocean of them! We spent hours picking them.But the supply of dandelions (蒲公英) never 3 .My father would cut off all the heads with the lawnmower (割草机) once a week,but that didn’t 4 these hardy wonders.
And for those flowers that escaped the honour of being 5 to my mother or the destiny to be killed by the lawnmower,there was another 6 of existence.The emergence of a new dandelion caused endless amazement as we had thought all were 7 .
As I worked in my garden last week,I again 8 at the flowers.And I hope I had the
9 of a dandelion.If only I could stretch my roots so deep that nothing could 10 me completely from the source that feeds me life.If only I could face the world with a sunshiny face after someone has run me over with a 11 .If only I could spread love as freely as this flower spreads seeds of itself.
The lawns are now beautiful green 12 .The only patches (块) of colour come from well-placed and well-controlled flowerbeds.Chemicals have managed to kill what human
13 couldn’t.I hope you and I can be 14 .I hope that we can stretch our roots deep enough so that the strongest poison can’t reach our 15 .I hope that we can overcome the poisons of anger,fear,hate,and competitiveness.
( )1.[A] changed [B] faded
[C] remained [D] uplifted
( )2.[A] presence [B] absence
[C] survival [D] removal
( )3.[A] pulled up [B] settled down
[C] got across [D] ran out
( )4.[A] distract [B] destroy
[C] trouble [D] restore
( )5.[A] hand-washed [B] hand-written
[C] hand-delivered [D] hand-crafted
( )6.[A] dimension [B] addition
[C] anticipation [D] exception
( )7.[A] amazing [B] thriving
[C] brilliant [D] gone
( )8.[A] grabbed [B] yelled
[C] marveled [D] laughed
( )9.[A] productivity [B] perseverance
[C] inclusiveness [D] effectiveness
( )10.[A] separate [B] discourage
[C] defend [D] forbid
( )11.[A] truck [B] block
[C] lawnmower [D] dandelion
( )12.[A] boards [B] routes
[C] blankets [D] signs
( )13.[A] evolution [B] interference
[C] preservation [D] enhancement
( )14.[A] forgiving [B] conventional
[C] emotional [D] different
( )15.[A] souls [B] deadlines
[C] fields [D] targets
Unit 5 Revealing nature
Ⅰ.阅读理解(每题2.5分,共30分)
A
Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night.This solves the problem of how to portion out (分配) energy reserves during the night so that the plant can keep growing,yet not risk burning off all its stored energy.
While the sun shines,plants perform photosynthesis (光合作用).In this process,the plants change sunlight,water and carbon dioxide into stored energy in the form of long chains of sugar,called starch (淀粉).At night,the plants burn this stored starch to fuel continued growth.
“The calculations are precise so that plants not only prevent starvation but also make the most efficient use of their food,” said study co-author Alison Smith.“If the starch store is used too fast,plants will starve and stop growing during the night.If the store is used too slowly,some of it will be wasted.”
The scientists studied the plant Arabidopsis (拟南芥),which is regarded as a model plant for experiments.To give the plants some math tests,the biologists let night arrive unexpectedly early or late for them.
During one of the exams,they shut off the lights early on plants that had been grown with twelve-hour days and nights.Putting them into darkness after only an eight-hour day meant they didn’t have time to store as much starch as usual.And this forced the plants to adjust their normal night rhythm.
Amazingly,even after this day length trick,the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night.They had neither starved,nor stored starch that could have been used to fuel more growth.
The authors suggested that similar biological calculators may explain how a migratory bird,the little stint (滨鹬),can make a five-thousand-kilometre journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more,on average.
[语篇导读] 本文是说明文。文章介绍了植物体内有类似生物计算器的控制系统来控制能量消耗。
( )1.According to the passage,plants .
[A] use little energy during the day
[B] usually stop growing at night
[C] waste a lot of energy at night
[D] store starch during the day
【答案】 D
【解析】 细节理解题。根据第二段中的“While the sun shines,plants...called starch (淀粉).”可知,在白天阳光照射时,植物进行光合作用储存淀粉。故选D。
( )2.What did the scientists do when studying Arabidopsis
[A] They changed the plants’ light conditions.
[B] They provided the plants with more starch.
[C] They tried to keep the plants’ natural rhythm.
[D] They attached a biological calculator to the plants.
【答案】 A
【解析】 细节理解题。根据第四段最后一句可知,在研究拟南芥时,科学家们让夜晚出乎意料地提早或晚到,即他们改变了植物的光照条件。故选A。
( )3.When morning arrived,the experimental plants .
[A] nearly died of lack of food
[B] used most of their stored energy
[C] began to regulate their food store
[D] stored enough starch for the next day
【答案】 B
【解析】 细节理解题。根据第二段最后一句可知,在晚上,植物消耗这些储存的淀粉,以促进其继续生长。再根据倒数第二段内容可知,实验植物只剩下5%的淀粉,说明它们使用了大部分储存的能量。故选B。
( )4.The passage mainly tells us .
[A] plants feel hungrier day by day
[B] plants are good at storing energy
[C] plants do math to survive the night
[D] plants use starch to fuel their growth
【答案】 C
【解析】 主旨大意题。根据第一段内容以及下文对控制能量消耗的植物控制系统的介绍可知,植物通过生物过程将储存的能量除以夜晚的长度,以此来控制能量消耗并促进生长。故选C。
B
The colour blue is very rare in nature,with fewer than one in ten plants sporting the colour universally favoured by humans.To present this colour,they have to perform tricks to make themselves blue to the human eyes.In some flowers like bluebells,it primarily occurs when naturally occurring pigments (色素) are mixed the way you can mix different paints to change the colour.
For blueberries,the blue colour comes from the naturally produced thin layer of wax (蜡) on their skin,which often serves as a self-cleaning coating or for added protection in the plant kingdom.“The blue colour of most fruits is in their pigmented juices.That isn’t the case with blueberries,” says Rox Middleton,co-author of a study published in a scientific journal.
In the study,Middleton and his team examined the wax of a blueberry using an electron microscope.They found that the layer of wax is composed of tiny structures that work by scattering (散射) blue and UV light from the sun,while absorbing most of other colours of light.The arrangement makes the berries appear blue to humans and blue-UV to birds and other species that can see UV light,despite not having blue pigments in the waxy skin itself.
To look closer,they removed the outer wax and reshaped it on a black card.They created a new blue-UV coating and removed a very thin substance that creates colour called a colorant from the skin.“The colorants scatter blue and UV,letting the other colours pass through without absorption,” says Middleton.“That’s why it’s so important that there are dark pigments underneath to ‘mop up’ the rest of the light.If there was a bright pigment or white scattering material underneath,that light would come through,and the colour would look mixed or washed out.”
The study does show that nature has developed a “really neat trick” in the form of a very thin layer for an important colorant.Reproducing this colorant in the lab could make a way for new methods of creating pigments.
[语篇导读] 本文是说明文。文章主要以蓝莓为例介绍了自然界中蓝色植物的罕见性以及它们如何以独特的方式展现蓝色。
( )5.How do bluebells present blue to humans
[A] By blocking natural light.
[B] By combining the pigments.
[C] By changing the outer colour.
[D] By producing various paints.
【答案】 B
【解析】 细节理解题。根据文章第一段最后一句可知,风信子通过混合色素将蓝色呈现给人类。故选B。
( )6.What did Middleton’s team discover about the wax layer on blueberries
[A] Its colourful pigments.
[B] Its internal mechanism.
[C] Its chemical changes.
[D] Its unique components.
【答案】 B
【解析】 细节理解题。根据文章第三段内容可知,Middleton及其团队通过电子显微镜研究蓝莓表皮后发现,蓝莓表皮的蜡质层通过散射蓝色和紫外线,吸收其他颜色光线的方式,使其对人类而言,看起来是蓝色的,而对能看到紫外线的鸟类和其他生物来说,除了蓝色外,它们还能看到蓝莓表面的紫外线光。由此可知,Middleton的团队发现了蓝莓蜡层的内部机制。故选B。
( )7.Which of the following can replace the underlined phrase “mop up” in Paragraph 4
[A] Mix. [B] Reflect.
[C] Recognise. [D] Absorb.
【答案】 D
【解析】 猜测短语题。根据画线词组所在段Middleton 所说的话可知,这些着色剂会散射蓝色和紫外线,让其他颜色的光线通过而不被吸收,这就是在它们表皮下面有深色色素来吸收剩余光线是如此重要的原因。根据语境和常识可知,表皮下面的深色色素是用来吸收剩余光线的。由此可知,mop up意为“吸收”。故选D。
( )8.What is a suitable title for the text
[A] The Science Behind Plant Colours
[B] The Invisible Pigments of Blueberries
[C] Technically,Blueberries Aren’t Blue
[D] Indeed,Colour Blue Is Humans’ Favourite
【答案】 C
【解析】 标题归纳题。根据文章第二段内容及文章最后一段中的第一句可知,文章主要以蓝莓为例介绍了自然界中蓝色植物的罕见性以及它们如何以独特的方式展现蓝色。研究人员通过电子显微镜研究蓝莓表皮后发现,蓝莓表皮上的蜡质层通过散射蓝色和紫外线,吸收其他颜色光线的方式,使得蓝莓对人类而言,看起来是蓝色的,而对能看到紫外线的鸟类和其他生物来说,除了蓝色外,它们还能看到蓝莓表面的紫外线光。由此可知,C项“从技术上讲,蓝莓不是蓝色的”适合作本文标题。故选C。
C
Every August the clustered carline thistle (蓟) is one of the plants that flower in most of Spain’s dry Mediterranean habitats,making it a dominant plant for the local bees and other pollinators.But how can the thistle survive,much less flower,when its neighbours are reduced to twigs and dust
Spanish National Research Council evolutionary ecologist Herrera had an amazing discovery when one day he peered into a thistle blossom to see how much nectar was inside and lightly touched the flower.He discovered that even after hours in direct sun,the flower heads were routinely five degrees cooler than their surroundings during the heat of the day,with the difference approaching 10 degrees for some flowers on the hottest days.
Sanna Sevanto,a physicist and plant physiologist,says that Herrera’s finding is exciting and could confirm a risky plant survival strategy that has,until now,only been theorised.
Sevanto and other scientists have documented that to perform photosynthesis (光合作用),leaves need access to carbon dioxide,which enters through tiny pores (细孔) called stomata on the leaf’s surface.When stomata open to let carbon dioxide in,some water escapes; this causes evaporative cooling that lowers the leaf’s temperature slightly.
But for the Spanish thistle,evaporative cooling could be the goal rather than just a side effect of photosynthesis.Herrera suggests the plant could essentially be sweating: sacrificing precious water,so scarce in Spain’s dry summers,to prevent its delicate reproductive organs from overheating.He adds that some flower species have stomata on their petals,which Sevanto says would be an easy route for releasing water.Opening stomata in a drought is a big gamble,though,and he notes that,so far,“we have not observed a plant that would do it to cool themselves.”
As heat waves become more frequent and intense with climate change,it’s increasingly important to study unusual adaptations that help plants survive heat stress.But ultimately,“whether these plants will have water enough to keep the system working,” Herrera says,“that’s another story.”
[语篇导读] 本文是说明文。文章主要介绍了在西班牙大部分干燥的地中海栖息地,聚集的蓟是开花的植物之一,使其成为当地蜜蜂和其他传粉者的优势植物。研究发现,蓟在炎热的天气会打开气孔是为了冷却关键器官,从而使其在高温胁迫下生存。
( )9.What was Herrera’s discovery about carline thistle in during the hottest days
[A] It was the only plant that blossomed.
[B] It was the only plant that survived.
[C] It had little nectar in the flower.
[D] It had lower temperature in the flower head.
【答案】 D
【解析】 细节理解题。根据第二段最后一句可知,Herrera在最炎热的天气发现了蓟的花冠温度较低。故选D。
( )10.Why does carline thistle open stomata in hot weather
[A] To cool the key organs.
[B] To take in carbon dioxide.
[C] To accelerate photosynthesis.
[D] To reduce water content in leaves.
【答案】 A
【解析】 细节理解题。根据倒数第三段最后一句及倒数第二段整体内容可知,蓟在炎热的天气会打开气孔是为了冷却关键器官。故选A。
( )11.What does the underlined word “gamble” in Paragraph 5 refer to
[A] Advantage. [B] Risk.
[C] Shift. [D] Evolution.
【答案】 B
【解析】 猜测词义题。根据画线词的下文及最后一段Herrera说的话可知,在干旱中打开气孔是一场大赌博,即是具有风险的,因此画线词和risk“风险”意思相近。故选B。
( )12.What is Herrera’s attitude towards the plants’ way to adapt to heat stress
[A] Suspicious. [B] Positive.
[C] Objective. [D] Unconcerned.
【答案】 C
【解析】 推理判断题。最后一段中提到随着气候变化,研究帮助植物在高温胁迫下生存的异常适应变得越来越重要,但是Herrera认为,这些植物是否有足够的水来维持系统工作就是另一个故事了。由此可推知,Herrera对植物适应高温胁迫的方式持客观态度。故选C。
Ⅱ.完形填空(每题1分,共15分)
I recall as a young child bringing a bunch of brilliant flowers to my mother.She was amazed at its shape but her passion eventually 1 .Both my parents hated the 2 of these flowers in the lawn.
There were an ocean of them! We spent hours picking them.But the supply of dandelions (蒲公英) never 3 .My father would cut off all the heads with the lawnmower (割草机) once a week,but that didn’t 4 these hardy wonders.
And for those flowers that escaped the honour of being 5 to my mother or the destiny to be killed by the lawnmower,there was another 6 of existence.The emergence of a new dandelion caused endless amazement as we had thought all were 7 .
As I worked in my garden last week,I again 8 at the flowers.And I hope I had the
9 of a dandelion.If only I could stretch my roots so deep that nothing could 10 me completely from the source that feeds me life.If only I could face the world with a sunshiny face after someone has run me over with a 11 .If only I could spread love as freely as this flower spreads seeds of itself.
The lawns are now beautiful green 12 .The only patches (块) of colour come from well-placed and well-controlled flowerbeds.Chemicals have managed to kill what human
13 couldn’t.I hope you and I can be 14 .I hope that we can stretch our roots deep enough so that the strongest poison can’t reach our 15 .I hope that we can overcome the poisons of anger,fear,hate,and competitiveness.
[语篇导读] 本文是夹叙夹议文。文章主要讲述了作者回忆童年时期对蒲公英的喜爱与父母对它的厌恶,引申出对生命力顽强、坚韧不拔精神的赞美,表达了作者希望像蒲公英一样拥有深深扎根、无畏困难、传播爱与阳光的生活态度。
( )1.[A] changed [B] faded
[C] remained [D] uplifted
【答案】 B
【解析】 根据下文的“Both my parents hated...in the lawn.”可知,此处表示母亲对于花的热情消退(faded)了。故选B。
( )2.[A] presence [B] absence
[C] survival [D] removal
【答案】 A
【解析】 根据下文的“My father would...once a week”可知,父亲每周都会割掉蒲公英,所以此处表示父母讨厌草坪上有(presence)这些花。故选A。
( )3.[A] pulled up [B] settled down
[C] got across [D] ran out
【答案】 D
【解析】 根据上文的“We spent hours picking them.But the supply of dandelions (蒲公英) never”以及下文的“My father would cut off...these hardy wonders.”可知,此处表示蒲公英永远也无法被除尽(ran out)。故选D。
( )4.[A] distract [B] destroy
[C] trouble [D] restore
【答案】 B
【解析】 根据下文的“The emergence of a new...all were 7 .”可知,割草机并不能消灭(destroy)所有的蒲公英。故选B。
( )5.[A] hand-washed [B] hand-written
[C] hand-delivered [D] hand-crafted
【答案】 C
【解析】 根据上文的“I recall as a young...to my mother.”可知,此处指作者亲手送给(hand-delivered)母亲的花。故选C。
( )6.[A] dimension [B] addition
[C] anticipation [D] exception
【答案】 A
【解析】 根据下文以及语境可知,除了被摘掉送给作者的母亲和被作者的父亲用割草机割掉外,蒲公英还有另一种存在层面(dimension)。故选A。
( )7.[A] amazing [B] thriving
[C] brilliant [D] gone
【答案】 D
【解析】 根据上文的“My father would...once a week”以及常识可知,经过割草机的切割之后,作者和父母以为蒲公英都被处理完,不复存在了。故选D。
( )8.[A] grabbed [B] yelled
[C] marveled [D] laughed
【答案】 C
【解析】 根据上文可知,此处表示作者再次对花感到惊奇(marveled)。故选C。
( )9.[A] productivity [B] perseverance
[C] inclusiveness [D] effectiveness
【答案】 B
【解析】 根据下文的“If only I could...feeds me life.”以及语境可知,此处指作者希望拥有蒲公英般的毅力(perseverance)。故选B。
( )10.[A] separate [B] discourage
[C] defend [D] forbid
【答案】 A
【解析】 根据下文的“me completely from the source that feeds me life”以及语境可知,此处表示作者认为没有任何东西可以将自己隔绝于(separate)生命源泉。故选A。
( )11.[A] truck [B] block
[C] lawnmower [D] dandelion
【答案】 C
【解析】 根据上文的“My father would cut...once a week”可知,此处呼应前文的割草机,表示如果有人使用割草机(lawnmower)碾过之后。故选C。
( )12.[A] boards [B] routes
[C] blankets [D] signs
【答案】 C
【解析】 根据上文的“The lawns are now beautiful green”以及下文的“The only patches (块) of...flowerbeds.”可知,此处将草坪比作绿色的地毯(blankets)。故选C。
( )13.[A] evolution [B] interference
[C] preservation [D] enhancement
【答案】 B
【解析】 根据上文的“Chemicals have managed to kill what human”可知,此处将人力干预(interference)与化学药品的作用进行对比。故选B。
( )14.[A] forgiving [B] conventional
[C] emotional [D] different
【答案】 D
【解析】 根据下文的“I hope that we can...competitiveness.”可知,此处表示作者希望人们都可以像蒲公英一样与众不同(different)。故选D。
( )15.[A] souls [B] deadlines
[C] fields [D] targets
【答案】 A
【解析】 根据上文的“I hope that we can stretch our...can’t reach our”以及语境可知,此处表示最烈的毒药也不会触及最深层的部分,即触及不到灵魂(souls)。故选A。
(
第
9
页
)(共65张PPT)
Unit 5 Revealing nature
题组训练
(限时35分钟 总分45分)
Ⅰ.阅读理解(每题2.5分,共30分)
A
Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night.This solves the problem of how to portion out (分配) energy reserves during the night so that the plant can keep growing,yet not risk burning off all its stored energy.
While the sun shines,plants perform photosynthesis (光合作用).In this process,the plants change sunlight,water and carbon dioxide into stored energy in the form of long chains of sugar,called starch (淀粉).At night,the plants burn this stored starch to fuel continued growth.
“The calculations are precise so that plants not only prevent starvation but also make the most efficient use of their food,” said study co-author Alison Smith.“If the starch store is used too fast,plants will starve and stop growing during the night.If the store is used too slowly,some of it will be wasted.”
The scientists studied the plant Arabidopsis (拟南芥),which is regarded as a model plant for experiments.To give the plants some math tests,the biologists let night arrive unexpectedly early or late for them.
During one of the exams,they shut off the lights early on plants that had been grown with twelve-hour days and nights.Putting them into darkness after only an eight-hour day meant they didn’t have time to store as much starch as usual.And this forced the plants to adjust their normal night rhythm.
Amazingly,even after this day length trick,the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night.They had neither starved,nor stored starch that could have been used to fuel more growth.
The authors suggested that similar biological calculators may explain how a migratory bird,the little stint (滨鹬),can make a five-thousand-kilometre journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more,on average.
[语篇导读]本文是说明文。文章介绍了植物体内有类似生物计算器的控制系统来控制能量消耗。
( )1.According to the passage,plants .
[A] use little energy during the day
[B] usually stop growing at night
[C] waste a lot of energy at night
[D] store starch during the day
D
【解析】 细节理解题。根据第二段中的“While the sun shines,plants...
called starch (淀粉).”可知,在白天阳光照射时,植物进行光合作用储存淀粉。故选D。
( )2.What did the scientists do when studying Arabidopsis
[A] They changed the plants’ light conditions.
[B] They provided the plants with more starch.
[C] They tried to keep the plants’ natural rhythm.
[D] They attached a biological calculator to the plants.
A
【解析】 细节理解题。根据第四段最后一句可知,在研究拟南芥时,科学家们让夜晚出乎意料地提早或晚到,即他们改变了植物的光照条件。故选A。
( )3.When morning arrived,the experimental plants .
[A] nearly died of lack of food
[B] used most of their stored energy
[C] began to regulate their food store
[D] stored enough starch for the next day
B
【解析】 细节理解题。根据第二段最后一句可知,在晚上,植物消耗这些储存的淀粉,以促进其继续生长。再根据倒数第二段内容可知,实验植物只剩下5%的淀粉,说明它们使用了大部分储存的能量。故选B。
( )4.The passage mainly tells us .
[A] plants feel hungrier day by day
[B] plants are good at storing energy
[C] plants do math to survive the night
[D] plants use starch to fuel their growth
C
【解析】 主旨大意题。根据第一段内容以及下文对控制能量消耗的植物控制系统的介绍可知,植物通过生物过程将储存的能量除以夜晚的长度,以此来控制能量消耗并促进生长。故选C。
B
The colour blue is very rare in nature,with fewer than one in ten plants sporting the colour universally favoured by humans.To present this colour,they have to perform tricks to make themselves blue to the human eyes.In some flowers like bluebells,it primarily occurs when naturally occurring pigments (色素) are mixed the way you can mix different paints to change the colour.
For blueberries,the blue colour comes from the naturally produced thin layer of wax (蜡) on their skin,which often serves as a self-cleaning coating or for added protection in the plant kingdom.“The blue colour of most fruits is in their pigmented juices.That isn’t the case with blueberries,” says Rox Middleton,co-author of a study published in a scientific journal.
In the study,Middleton and his team examined the wax of a blueberry using an electron microscope.They found that the layer of wax is composed of tiny structures that work by scattering (散射) blue and UV light from the sun,while absorbing most of other colours of light.The arrangement makes the berries appear blue to humans and blue-UV to birds and other species that can see UV light,despite not having blue pigments in the waxy skin itself.
To look closer,they removed the outer wax and reshaped it on a black card.They created a new blue-UV coating and removed a very thin substance that creates colour called a colorant from the skin.“The colorants scatter blue and UV,letting the other colours pass through without absorption,” says Middleton.“That’s why it’s so important that there are dark pigments underneath to ‘mop up’ the rest of the light.If there was a bright pigment or white scattering material underneath,that light would come through,and the colour would look mixed or washed out.”
The study does show that nature has developed a “really neat trick” in the form of a very thin layer for an important colorant.Reproducing this colorant in the lab could make a way for new methods of creating pigments.
[语篇导读]本文是说明文。文章主要以蓝莓为例介绍了自然界中蓝色植物的罕见性以及它们如何以独特的方式展现蓝色。
( )5.How do bluebells present blue to humans
[A] By blocking natural light.
[B] By combining the pigments.
[C] By changing the outer colour.
[D] By producing various paints.
B
【解析】细节理解题。根据文章第一段最后一句可知,风信子通过混合色素将蓝色呈现给人类。故选B。
( )6.What did Middleton’s team discover about the wax layer on blueberries
[A] Its colourful pigments.
[B] Its internal mechanism.
[C] Its chemical changes.
[D] Its unique components.
B
【解析】 细节理解题。根据文章第三段内容可知,Middleton及其团队通过电子显微镜研究蓝莓表皮后发现,蓝莓表皮的蜡质层通过散射蓝色和紫外线,吸收其他颜色光线的方式,使其对人类而言,看起来是蓝色的,而对能看到紫外线的鸟类和其他生物来说,除了蓝色外,它们还能看到蓝莓表面的紫外线光。由此可知,Middleton的团队发现了蓝莓蜡层的内部机制。故选B。
( )7.Which of the following can replace the underlined phrase “mop up” in Paragraph 4
[A] Mix.
[B] Reflect.
[C] Recognise.
[D] Absorb.
D
【解析】 猜测短语题。根据画线词组所在段Middleton 所说的话可知,这些着色剂会散射蓝色和紫外线,让其他颜色的光线通过而不被吸收,这就是在它们表皮下面有深色色素来吸收剩余光线是如此重要的原因。根据语境和常识可知,表皮下面的深色色素是用来吸收剩余光线的。由此可知,mop up意为“吸收”。故选D。
( )8.What is a suitable title for the text
[A] The Science Behind Plant Colours
[B] The Invisible Pigments of Blueberries
[C] Technically,Blueberries Aren’t Blue
[D] Indeed,Colour Blue Is Humans’ Favourite
C
【解析】标题归纳题。根据文章第二段内容及文章最后一段中的第一句可知,文章主要以蓝莓为例介绍了自然界中蓝色植物的罕见性以及它们如何以独特的方式展现蓝色。研究人员通过电子显微镜研究蓝莓表皮后发现,蓝莓表皮上的蜡质层通过散射蓝色和紫外线,吸收其他颜色光线的方式,使得蓝莓对人类而言,看起来是蓝色的,而对能看到紫外线的鸟类和其他生物来说,除了蓝色外,它们还能看到蓝莓表面的紫外线光。由此可知,C项“从技术上讲,蓝莓不是蓝色的”适合作本文标题。故选C。
C
Every August the clustered carline thistle (蓟) is one of the plants that flower in most of Spain’s dry Mediterranean habitats,making it a dominant plant for the local bees and other pollinators.But how can the thistle survive,much less flower,when its neighbours are reduced to twigs and dust
Spanish National Research Council evolutionary ecologist Herrera had an amazing discovery when one day he peered into a thistle blossom to see how much nectar was inside and lightly touched the flower.He discovered that even after hours in direct sun,the flower heads were routinely five degrees cooler than their surroundings during the heat of the day,with the difference approaching 10 degrees for some flowers on the hottest days.
Sanna Sevanto,a physicist and plant physiologist,says that Herrera’s finding is exciting and could confirm a risky plant survival strategy that has,until now,only been theorised.
Sevanto and other scientists have documented that to perform photosynthesis (光合作用),leaves need access to carbon dioxide,which enters through tiny pores (细孔) called stomata on the leaf’s surface.When stomata open to let carbon dioxide in,some water escapes; this causes evaporative cooling that lowers the leaf’s temperature slightly.
But for the Spanish thistle,evaporative cooling could be the goal rather than just a side effect of photosynthesis.Herrera suggests the plant could essentially be sweating: sacrificing precious water,so scarce in Spain’s dry summers,to prevent its delicate reproductive organs from overheating.He adds that some flower species have stomata on their petals,which Sevanto says would be an easy route for releasing water.Opening stomata in a drought is a big gamble,though,and he notes that,so far,“we have not observed a plant that would do it to cool themselves.”
As heat waves become more frequent and intense with climate change,it’s increasingly important to study unusual adaptations that help plants survive heat stress.But ultimately,“whether these plants will have water enough to keep the system working,” Herrera says,“that’s another story.”
[语篇导读]本文是说明文。文章主要介绍了在西班牙大部分干燥的地中海栖息地,聚集的蓟是开花的植物之一,使其成为当地蜜蜂和其他传粉者的优势植物。研究发现,蓟在炎热的天气会打开气孔是为了冷却关键器官,从而使其在高温胁迫下生存。
( )9.What was Herrera’s discovery about carline thistle in during the hottest days
[A] It was the only plant that blossomed.
[B] It was the only plant that survived.
[C] It had little nectar in the flower.
[D] It had lower temperature in the flower head.
D
【解析】细节理解题。根据第二段最后一句可知,Herrera在最炎热的天气发现了蓟的花冠温度较低。故选D。
( )10.Why does carline thistle open stomata in hot weather
[A] To cool the key organs.
[B] To take in carbon dioxide.
[C] To accelerate photosynthesis.
[D] To reduce water content in leaves.
A
【解析】 细节理解题。根据倒数第三段最后一句及倒数第二段整体内容可知,蓟在炎热的天气会打开气孔是为了冷却关键器官。故选A。
( )11.What does the underlined word “gamble” in Paragraph 5 refer to
[A] Advantage.
[B] Risk.
[C] Shift.
[D] Evolution.
B
【解析】 猜测词义题。根据画线词的下文及最后一段Herrera说的话可知,在干旱中打开气孔是一场大赌博,即是具有风险的,因此画线词和risk“风险”意思相近。故选B。
( )12.What is Herrera’s attitude towards the plants’ way to adapt to heat stress
[A] Suspicious.
[B] Positive.
[C] Objective.
[D] Unconcerned.
C
【解析】推理判断题。最后一段中提到随着气候变化,研究帮助植物在高温胁迫下生存的异常适应变得越来越重要,但是Herrera认为,这些植物是否有足够的水来维持系统工作就是另一个故事了。由此可推知,Herrera对植物适应高温胁迫的方式持客观态度。故选C。
Ⅱ.完形填空(每题1分,共15分)
I recall as a young child bringing a bunch of brilliant flowers to my mother.She was amazed at its shape but her passion eventually 1 .Both my parents hated the 2 of these flowers in the lawn.
There were an ocean of them! We spent hours picking them.But the supply of dandelions (蒲公英) never 3 .My father would cut off all the heads with the lawnmower (割草机) once a week,but that didn’t 4 these hardy wonders.
And for those flowers that escaped the honour of being 5 to my mother or the destiny to be killed by the lawnmower,there was another
6 of existence.The emergence of a new dandelion caused endless amazement as we had thought all were 7 .
As I worked in my garden last week,I again 8 at the flowers.And I hope I had the 9 of a dandelion.If only I could stretch my roots so deep that nothing could 10 me completely from the source that feeds me life.If only I could face the world with a sunshiny face after someone has run me over with a 11 .If only I could spread love as freely as this flower spreads seeds of itself.
The lawns are now beautiful green 12 .The only patches (块) of colour come from well-placed and well-controlled flowerbeds.Chemicals have managed to kill what human 13 couldn’t.I hope you and I can be 14 .I hope that we can stretch our roots deep enough so that the strongest poison can’t reach our 15 .I hope that we can overcome the poisons of anger,fear,hate,and competitiveness.
【语篇导读】本文是夹叙夹议文。文章主要讲述了作者回忆童年时期对蒲公英的喜爱与父母对它的厌恶,引申出对生命力顽强、坚韧不拔精神的赞美,表达了作者希望像蒲公英一样拥有深深扎根、无畏困难、传播爱与阳光的生活态度。
( )1.[A] changed [B] faded
[C] remained [D] uplifted
B
【解析】 根据下文的“Both my parents hated...in the lawn.”可知,此处表示母亲对于花的热情消退(faded)了。故选B。
( )2.[A] presence [B] absence
[C] survival [D] removal
A
【解析】 根据下文的“My father would...once a week”可知,父亲每周都会割掉蒲公英,所以此处表示父母讨厌草坪上有(presence)这些花。故选A。
( )3.[A] pulled up [B] settled down
[C] got across [D] ran out
D
【解析】 根据上文的“We spent hours picking them.But the supply of dandelions (蒲公英) never”以及下文的“My father would cut off...these hardy wonders.”可知,此处表示蒲公英永远也无法被除尽(ran out)。故选D。
( )4.[A] distract [B] destroy
[C] trouble [D] restore
B
【解析】 根据下文的“The emergence of a new...all were 7 .”可知,割草机并不能消灭(destroy)所有的蒲公英。故选B。
( )5.[A] hand-washed [B] hand-written
[C] hand-delivered [D] hand-crafted
C
【解析】 根据上文的“I recall as a young...to my mother.”可知,此处指作者亲手送给(hand-delivered)母亲的花。故选C。
( )6.[A] dimension [B] addition
[C] anticipation [D] exception
A
【解析】 根据下文以及语境可知,除了被摘掉送给作者的母亲和被作者的父亲用割草机割掉外,蒲公英还有另一种存在层面(dimension)。故选A。
( )7.[A] amazing [B] thriving
[C] brilliant [D] gone
D
【解析】 根据上文的“My father would...once a week”以及常识可知,经过割草机的切割之后,作者和父母以为蒲公英都被处理完,不复存在了。
故选D。
( )8.[A] grabbed [B] yelled
[C] marveled [D] laughed
C
【解析】 根据上文可知,此处表示作者再次对花感到惊奇(marveled)。故选C。
( )9.[A] productivity [B] perseverance
[C] inclusiveness [D] effectiveness
B
【解析】 根据下文的“If only I could...feeds me life.”以及语境可知,此处指作者希望拥有蒲公英般的毅力(perseverance)。故选B。
( )10.[A] separate [B] discourage
[C] defend [D] forbid
A
【解析】 根据下文的“me completely from the source that feeds me life”以及语境可知,此处表示作者认为没有任何东西可以将自己隔绝于(separate)生命源泉。故选A。
( )11.[A] truck [B] block
[C] lawnmower [D] dandelion
C
【解析】根据上文的“My father would cut...once a week”可知,此处呼应前文的割草机,表示如果有人使用割草机(lawnmower)碾过之后。故选C。
( )12.[A] boards [B] routes
[C] blankets [D] signs
C
【解析】 根据上文的“The lawns are now beautiful green”以及下文的“The only patches (块) of...flowerbeds.”可知,此处将草坪比作绿色的地毯(blankets)。故选C。
( )13.[A] evolution [B] interference
[C] preservation [D] enhancement
B
【解析】根据上文的“Chemicals have managed to kill what human”可知,此处将人力干预(interference)与化学药品的作用进行对比。故选B。
( )14.[A] forgiving [B] conventional
[C] emotional [D] different
D
【解析】 根据下文的“I hope that we can...competitiveness.”可知,此处表示作者希望人们都可以像蒲公英一样与众不同(different)。故选D。
( )15.[A] souls [B] deadlines
[C] fields [D] targets
A
【解析】根据上文的“I hope that we can stretch our...can’t reach our”以及语境可知,此处表示最烈的毒药也不会触及最深层的部分,即触及不到灵魂(souls)。故选A。
