(共28张PPT)
Revealing nature
Using Language
Unit 5
Learning Objectives
01
Learning Objectives
Master the usage of key words in this lesson—characteristic, decline, blame, primitive—and key phrases—be native to, make important discoveries, in particular, be harmful to, be home to, by contrast, grow up to, carry out, serve as—and be able to use them flexibly in real contexts.
Master the usage of the past perfect tense.
Help students understand topic content related to species diversity and the natural world, and be able to appropriately use functional expressions to ask for information and supplement information.
Through learning, help students understand biological diversity, inspire their enthusiasm for exploring the mysteries of nature, and further cultivate their love for nature and awareness of protecting nature.
Key Points and Difficult Points
Key points:
The usage of the past perfect tense.
Difficult Points:
The usage of the past perfect tense.
Learning to use the key words, phrases and sentence patterns in this section.
Grammar
02
Look at the sentences from the reading passage and answer the question.
1. In sentence (a), which action happened first, “suspected” or “evolved from a common ancestor”
In sentence (a), “evolved from a common ancestor” happened first.
2. In sentence (b), which action happened first, “refused to believe” or “evolved from lower forms of life”
In sentence (b), “evolved from lower forms of life” happened first.
3. What does the structure had done indicate
It indicates the action happened before a certain past action.
Past perfect(过去完成时)
一、过去完成时的构成
过去完成时由“助动词 had(通用于各种人称和数)+过去分词”构成。
二、过去完成时的用法
1. 过去完成时表示在过去某一时间或某一动作之前已经完成的动作或存在的状态。
I had finished my homework before supper.
我在晚饭前就把作业做完了。
2. 过去完成时还可表示过去某一时刻之前发生的动作或状态持续到过去某个时间或还要持续下去,常用的时间状语有by then,by the end of等。
By the end of last week, she had learned 10 English songs
到上周为止,她已经学习了10 首英文歌曲。
Past perfect(过去完成时)
3. 用于表示与过去事实相反的虚拟条件从句中。
If he had seen you yesterday, he would have asked you about it.
假如他昨天看到你,他就会问你这件事了。
4. 过去完成时也用于hardly...when...,no sooner…than..., It was the first time+that(从)等一些固定句型中。
He had no sooner left the room than they began to talk about him.
他刚离开房间,他们就议论起他来
We had hardly begun when we were told to stop.
我们刚开始就被叫停
5. 表示未曾实现的希望、打算、意图、诺言、想法等,常用过去完成时。
I had hoped to see her again.
我本希望再见她一面。(没能如愿)
Past perfect(过去完成时)
三、过去完成时与现在完成时及一般过去时的区别
1. 过去完成时与现在完成时的区别。
现在完成时表示的动作发生在过去,以现在的时间为基点,但侧重对现在产生的结果或造成的影响,与现在有关,其结构为“助动词 have(has)+过去分词”;过去完成时则是一个相对的时态,以过去时间为基点,它所表示的动作不仅发生在过去,更强调“过去的过去”,只有和过去某时或某动作相比较时,才用到它。
比较:
I have learned 1,000 English words so far.
到目前为止我已经学会了1000个英语单词。
I had learned 1,000 English words till then
到那时为止我已经学会了1000个英语单词。
Past perfect(过去完成时)
2. 过去完成时与一般过去时的区别。
虽然这两种时态都表示过去发生的动作或存在的状态,但在使用时应注意以下几点:
(1)时间状语不同:过去完成时在时间上强调“过去的过去”,而一般过去时只强调过去某一特定的时间。比较:
They had arrived at the station by ten yesterday.
他们昨天十点之前就已经到达车站了。
They arrived at the station at ten yesterday.
他们昨天十点到达车站。
(2)在没有明确的过去时间状语作标志时,谓语动词动作发生的时间先后须依据上下文来判断:先发生的用过去完成时,后发生的则用一般过去时。
She had just won the first prize in the composition competition. She was very happy. Her whole family were pleased with her, too.
她刚刚在作文竞赛中获得了一等奖。她很高兴,她的所有家人也对她感到满意。
Complete the paragraphs with the information from the given sentences. The sentences are in the order in which they happened. They can help you to decide the use of tenses.
began
had led to
developed
chose to
had made
Complete the online encyclopaedia entry with the correct form of the words in the box.
Lonesome George
Lonesome George was the last Pinta Island tortoise. He died in 2012. After George’s death, the Pinta Island tortoise was declared extinct.
The extinction of the Pinta Island tortoise is blamed on humans. Before humans 1________ on the island, the species 2_________ in isolation and 3__________ the plants that naturally grew there. George was discovered many years after their arrival, and by then humans 4_____________ new species that 5__________ for the food the tortoises ate. After goats in particular had been brought to the island, the Pinta Island tortoise population 6___________. Eventually, only George remained.
arrived
had lived
eaten
had introduced
competed
declined
compete decline eat live introduce arrive
Listening
03
Listen to the podcast and choose the statements that are made.
Biodiversity is important.
Bacteria are always harmful to humans.
Some species of bacteria are used in food production.
Many species of bacteria recycle dead organic matter.
Our immune systems are able to fight off all germs.
Listen again and complete the fact sheet.
Cells
Every living thing is 1 __________________________.
They are like 2 _________________________________.
In the human body there are about 3 _________________ human cells and around 4 _________________________ bacteria cells.
Bacteria
Most bacteria in the human body can 5 _____________________.
In the food production process, bacteria can 6 ______________ dead organic matter.
made up of cells
bricks that are used to build houses
thirty trillion
thirty-nine trillion
help with digestion
break down
Now work in pairs. Discuss what you know about cells and bacteria.
Complete the boxes with the expressions from the podcast.
Checking background knowledge
Adding information
Do you know about...
Have you heard of...
By the way, ...
In fact, ...
Actually, ...
Speaking of which, ...
Read the passage and answer the questions.
1. What species are mentioned and what is special about them
Two species are mentioned: the blue whale and the water bear. The blue whale is the largest animal species on Earth, which can grow up to almost 30 metres in length and weigh over 130,000 kilos. The water bear is probably the toughest species, which can survive temperatures from 150C to a below freezing -272℃.
2. What other unusual life forms do you know of
Complete the paragraphs with the correct form of the words and expressions in the box.
The Galápagos Islands are renowned worldwide for their unique biodiversity. The Giant Tortoise Reserve on Santa Cruz 1___________ several species of giant tortoise that 2___________ the Galápagos Islands. The island is also home to the Charles Darwin Research Station, where 3___________ studies are carried out.
Mangroves are one of the coastal plants that grow on Isabela. They serve as the 4__________ for various birds and fish, and are very important to the 5___________.
Lguanas can be found on San Cristóbal. They have a very special 6____________, with comb-like spines on their back. There is evidence that all the different iguanas have developed from more 7__________ ones and share a common 8_____________.
is home to
are native to
scientific
habitats
ecosystem
appearance
primitive
ancestor
Work in pairs. Look at the pictures of the species native to different regions of China. Talk about biodiversity in China using the words and expressions in this section. Do online research to find more information.
Now talk about what methods you used to collect the information pare your methods with your partner’s and think about which methods are more efficient.
Vocabulary
1. decline
decline v.减少
decline by... 减少了……
decline to... 减少到……
decline in... 在……方面降低
decline to do sth. 拒绝做某事
例题:According to the latest report, the number of endangered birds in this area has declined ______ 20% over the past five years.
根据最新报告,过去五年间该地区濒危鸟类的数量已下降了 20%。
by
Vocabulary
2. blame
blame v.责怪,指责;把……归咎于
blame sb./sth. for sth. 把某事归咎于某人/某物
blame sb. for (doing) sth. 因(做)某事而责备某人
take/accept the blame ( for sth.) 承担(某事的)责任
put/lay/place the blame on sb. 把责任归于某人
the blame lies with sb. 责任在于某人
例题:
The coach blamed the players for ______ (lose) the important match yesterday.
losing
Exercise
04
Exercise
We ___________ (paint) the house before we __________ (move) in.
Paul __________ (go) out with Jane after he __________ (make) a phone call.
Tom __________ (say) he __________ (read) the book twice.
他说自从 1989 年以来他就在那家工厂工作。
He said ______________________________ since 1989.
我认为我一星期前就把信寄出去了。
I thought _____________________________ a week before.
昨晚九点之前我已看完这本小说了。
____________________________ by nine o'clock last night.
had painted
moved
had made
went
said
had read
he had worked in that factory
I had sent the letter
I had finished reading the novel
Summary
05
Using language
Grammar
Listening
Vocabulary
过去完成时
构成
用法
过去完成时与现在完成时及一般过去时的区别
Homework
06
Review the language points and complete the exercises.
SEE YOU
NEXT CLASS!