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人教版英语-必修五-unit5知识点+练习
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男人噎了几下才喘过气来。
8. essential adj. 最重要的，不可缺少的，本质的
1)Sun and water are essential to the growth of 。
 2)It is essential for us to set our study 。
3)It is essential that you (should) win the voter's  。
-----当用it充当主语而用它充当表语时，that 从句的谓语动词用should +动词原形 。
9. You have three layers of skin which act as a barrier against disease  act as  作为….
barrier 屏障,障碍物,隔阂
You should show the ticket at the barrier.
10. poison n./vt. 毒药，毒害；毒害，使中毒
eg:1)Poisons must be put out of children’s reach. 2)This matter will make some poison to the 。
3)Books of this kind can make poison to children.
4)Heroin has poisoned a lot of people.
5)The polluted water in the river poisoned people 。
-----poisonous  adj. 有毒(害)的 
eg: This medicine is poisonous if taken in large quantities.
…against/ from…   保护…不受…的损害 prevent…from doing   阻止．．．
protect your eyes from strong light
prevent them from getting married
stop sb. (from) doing
keep sb. from doing
12. sense (n. & v.)
five senses：
sense of smell sense of hearing
the sixth sense sense of touch
sense of sight sense of taste
sense of humour、duty、direction
The man has no common sense . (无常识)
What he said made no sense.(没道理)
sense (v.)   感觉到
Although she didn’t say anything, I sensed that she didn’t like the idea. 
as you can imagine, if your skin gets burned, it can be very serious.
as引导非限制性定语从句，指代后面的内容，有“正如……”或“就象……”的意思；它所引
的从句位置较灵活，可以位于句首、句中或句末。
as we all know  = as  is known to all
as  we  expect  = as  is  expected
as everybody can see
as you can imagine
不同的，各种各样的
There are various colors to choose from.
vary  vi 1.～(in sth)- size, volume, strength, etc(体积、容积、力量等)呈现不同 
15. vary   ～(with sth); ～(from sth to sth)
Prices vary with seasons. 物价随季节而变动
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