人教版（2019）选择性必修第二册Unit 1 Science and scientists 单词练习课件(共25张PPT)

(共25张PPT)
人教选二Unit 1
Science and scientists
learn the words in the passage
Since the severe COVID-19 broke out , many people all over the world have been infected. Chinese outstanding, gifted and patriotic specialists in epidemiology and their assistants have been in charge of tracing the source of the virus in order to defend more people from being killed.
They desired to produce vaccine to handle the deadly disease once and for all. Initially, with concrete proof collected, they suspected that wild bats were to blame. But by observaing the virus with microscopes, they gathered solid and multiple statistics and mastered the framework of the virus, which gradually transformed their intial contradictory thinking.
All the findings made them suscribe to the idea that the virus was not directly linked to the bats, which made the brilliant experts frustrated. This also cast a shadow on the experts, so they had to shift towards how to prevent the virus from spreading among people.
Above all, the less we go out, the less likely we will come down with the deadly disease. Furthermore, taking in more protein and eating more vegetables are good choices as well.
Last but not least, what we should do is that we must wear masks outdoors. Thanks to these interventions, the threat of COVID-19 in China saw a susbtantial decrease.
What we have experienced has taught us to lead a healthy life such as drinking pure or boiled water and avoiding raw food.
In conclusion, under our motherland`s leadership, we have achieved steady success, tears of happiness pouring down our cheeks.
practice again
1 cholera
2 diarrhoea
3 dehydration
4 contradictory
5 germ
6 pump
7 water pump
8 household
9 raw
10 statistic
11 epdemiology
12 microscope
13 protein
14 cell
15 virus
16 vaccine
17 framework
18 theoretical framework
19 rainbow
20 concrete
21 plasma
22 aerospace
23 patriotic
24 mechanical
25 mechanic
26 aviation
27 jet
28 missile
29 astronomy
30 telescope
31 severe
32 idiom
33 ignore
34 initial
35 solid
36 shadow
37 subscribe
38 suspect
39 blame
40 handle
41 link
42 substantial
43 decrease
44 transform
45 thinking
46 finding
47 cast
48 pour
49 leadership
50 immigration
51 impression
52 incorrect
53 import
54 illegal
55 immediately
56 trace
57 outstanding
58 abstract
59 concept
60 besides
61 brilliant
62 furthermore
63 fault
64 shift
65 frustrated
66 infection
67 infectious
68 frustrate
69 defend
70 proof
71 prove
72 intervention
73 multiple
74 multiply
75 intervene
76 assistant
77 gifted
78 steady
79 vivid
80 once and for all
81 subscribe to
82 thanks to
83 break out
84 in charge of
85 come down
86 above all
87 die from
88 die of
89 in time
90 be likely to do
81 after all
82 in all
83 be to blame
84 come up with
85 come across
86 come out
Reading comprehension
Can graphene (石墨烯）in your clothing stop mosquito bites
With the weather getting hot, bites caused by mosquitoes not only annoy people, but can result in many infectious diseases. Even when people wear long clothes, mosquitoes` complex biting mechanism enables them to bite some of them through.
It would be great if clothing could be used to completely prevent people from getting betten. Researchers tested graphene , a material that is incredibly thin but really strong, in order to find out if it can make clothing resistant to mosquitoes.
In the lab experiment, volunteers exposed a small patch of skin on their arm or hand to roughly 100 mosquitoes for five minutes at a time. Researchers tested three different situations: volunteers wearing no protection, wearing cheesecloth(薄纱棉布）, or wearing cheesecloth plus a thin graphene layer under it.
A video camera was then used to record and quantify mosquitoes` behavior, including whether they landed on the skin, how long they stayed there , and whether they began to suck blood.The number of bites each volunteer got was also calculated based on how many swellings developed on their skin afterwards. Finally, researchers dropped a little water or sweat on top of the graphene layer and studied the consequence, and they also tested a slightly different graphene layer called “reduced graphene.”
As a result, the number of mostuito bites on naked skin was the highest, about 16 on average; skin only protected by cheesecloth got the second, approximately 10 per five minutes`exposure. The exciting finding was that there was no swelling developing on skin covered by the thin graphene layer under cheesecloth, which means the material is effective at preventing mosquito bites. The mosquitoes landed on skin totally uncovered or covered in cheesecloth about 23 times on average, and stayed for one to two minutes.
Comparatively, the mosquitoes landed on skin covered in the graphene layer fewer than 10 times, and the length of their stay was much shorter. Besides, water or sweat can ruin the graphene layer, which allows mosquitoes to bite through it. But fortunately, the number of mosquito bites in either dry or wet conditions can be lowered as long as the graphene material is improved to certain extent.
1 Why did researchers conduct the experiment
A To record the behavior of mosquitoes
B To find a substance to prevent mosquito bites.
C To find a solution to stop infectious diseases.
D To test graphene`s effectiveness in preventing mosquito bites.
2 What was the problem when water and sweat was applied to graphene
A It had no effect on graphene.
B It slightly affected graphene.
C It improved graphene a little.
D It made graphene totally useless.
3 In which way did researchers draw a conclusion
A By analyzing the reasons.
B By comparing the statistics.
C By classifying three situations.
D By recording mosquitoess` behavior.
4 Which of the following shows how the text is developed
A Cause-effect.
B Opinion-fact.
C Assumption-conclusion.
D Phenomenon-evaluation.
Thank you!