3. 引导让步状语从句，作“虽然，尽管”解。这时从句常用倒装语序，即把从句中的表语、状语或动词原形放在as之前。e.g.：
Strange as it may seem，it is true. 尽管这事看上去很奇怪，但却是真的
Try as he might，Tom could not get out of the difficulties. 不管怎样努力，汤姆还是摆脱不了困境。
(四)as作关系代词。
2. 引导原因状语从句，作“因为，由于”解，与because的用法相近。e.g.：
I must stop writing now，as I have rather a lot of work to do. 我必须停笔了，因为我还有许多工作要做。K^S*5U.C#O%下
引导方式状语从句或比较状语从句，作“正如，(如)像”解。e.g.：
As in your country，we grow wheat in the north and rice in the south. 正如(像)你们国家一样，我们在北方种小麦，在南方种水稻。(方式状语从句)
When at Rome，do as Romans do. 入乡随俗。(方式状语从句)
1. 引导时间状语从句，作“当……的时候”解，有“随着……”之意，与while意义相近，强调两个动作同时发生；或某事一发生，另一事立即发生。e.g.：
He shouted aloud as her ran along. 他一边往前跑，一边高声地呼喊。
I was startled as he opened the door. 他一开门，吓了我一跳。
as作连词，相当于when。e.g.：
As a little boy (When he was a little boy)he began to learn to play piano. 他小时候就开始学弹钢琴。
(二)as作介词。
作“如，像”解。e.g.：
They got united as one man.
作“充当，作为”解。e.g.：
As a writer，he was famous.
(三)as作连词，常用来连接主句和状语从句。
1. Do not rub, as this may break any blisters and the wound may get infected.不要擦拭，因为这样做会擦破水泡，伤口会感染
小结as的用法：
(一)as作副词，表示程度，意为“同样地”。在“as. . . as. . . ”，“not as. . . as. . . ”结构中的第一个as是副词，作“和／与……(不)一样”解。e.g.：
Jack is as tall as his father.
He doesn’t speak English as／so fluently as you.
4. stick to 粘住， 坚持
Take clothing off the burned area unless it is stuck to the burn.除非衣服粘贴在烧伤面上，否则都要把它脱掉。
Cover the burned area with a bandage that will not stick to the skin.用干而清洁又不粘皮肤的绷带把烧伤面包起来。
拓展：stick to, insist on, keep on
stick to a decision/ plan/ theory坚持决定/计划/理论(不改变)
insist on doing sth.坚持要做某事
Stick to what you think is right, no matter what others say.
He insisted on going home, though it was very late.
For many years he kept on studying English and using it until he could used it freely.
3. make a difference有影响， 很重要
It shows that a knowledge of first aid can make a real difference.这表明急救知识的确能发挥重要作用。
Everyone can make a difference as long as he tries to.只要努力，人人都可以有所作为。
拓展：
It makes no difference whether…是否……没有什么差别
= It doesn’t matter whether ….
如：It makes no difference whether you are for or against the arrangement.你反对还是赞成这安排都没有关系。(没用)
2. a number of adj.“许多的， 若干”后接可数名词
区别：the number of / a number of：
都跟可数名词复数。前者作主语，谓语用单数；后者作主语，谓语用复数。
The number of the trees is two thousand. (用单数谓语. 另注意trees前有限定词)
A number of trees have been cut down. (用复数谓语. 另注意trees前无限定词)
后接可数或不可数名词的短语：
1)lots of(a lot of)后接可数或不可数名词。例如：
My parents spend a lot of their spare time on English study.
Mike had collected lots of Chinese stamps when he studied in China.
2)plenty of后接可数或不可数名词。例如：
We have plenty of books to read.
There is plenty of water in apple.
(注：plenty of一般只用于肯定句，在疑问句中常改用 enough；在否定句中常改用 many或 much。另外， plenty of短语作主语时，谓语动词的数由它后面的名词的数而定。)
3)most of后接可数或不可数名词。例如：
Most of his money is spent on books.
Most of the students in our class are fond of sports.
4)a large quantity of后接可数或不可数名词。例如：
A large quantity of books have been translated into foreign languages.
There is a large quantity of coal in the coal－mine.
后只接可数名词的短语
1)a group of后接可数名词的复数。例如：
A group of wounded soldiers were saved by Dr Bethune.
2)a(great/large/good)number of后接可数名词的复数。例如：
There are a number of professors in our college.
A great(large／good) number of new machines have been sent to the country side.
3)a great many后接可数名词的复数。例如：
There are a great many books in our school library.
4)scores of后接可数名词的复数。例如：
Scores of dustmen took part in the strike.
后只接不可数名词的短语
1)a great(good deal of)后接不可数名词。例如：
A great deal of information can be stored in computers.
2)a large amount of 后接不可数名词。例如：
They are going to spend a large amount of time on the research work.
1. first aid
(1)n.(对伤患者的)急救
give first aid to sb.= carry out first aid on sb.对某人实施急救
拓展：aid n.帮助， 援助， 帮助者，有帮助的事物
cut off aid中止援助
teaching aids教具
a hearing aid助听器
medical aid医疗救护
with the aid of借助于= with the help of
come to sb.’s aid帮助某人
in aid of为了帮助
we collect money in aid of the education in the poverty-stricken area. 我们筹集资金以援助贫困地区的教育。K^S*5U.C#O%下
(2)vt.资助， 援助， 帮助
I aided him in his enterprise.
They aided in solving the problem.
2. present
(1)vt.赠予； 颁予， 呈递
present flowers to sb.(present sb. with flowers)献花给某人
present reasons提出理由
present a new aspect呈现出一派新气象
present a new play 上演一出新戏
Allow me to present Mr Black to you.请允许我向您介绍布莱克先生。
(2)adj.现在的， 出席的， 存在的
at the present time目前， 现在
the present price现价
the present participle现在分词
be present at a ceremony出席仪式
(3)n.礼物， 现在， 目前
at present现在， 目前
