AS的用法总结.ppt

As 用法小结
as用法归纳
as词性多,词义广,用法灵活。现将其用法归纳如下:
Ⅰ. 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。
①Jack is as tall as his father. ②He doesn’t speak English as/so fluently as you.
Ⅱ. As作连词,主要引导以下状语从句:
1. 引导时间状语从句。与while意义相近,强调两个动作同时发生;或某事一发生,另一事立刻发生。 ① He shouted aloud as he ran along. ② I was startled as he opened the door. ③ We get wiser as we get older.
2. 引导原因状语从句,与because的用法相近。

① As it was getting very late, we soon turned back. ② We must stop writing now, as I have rather a lot of work to do.
3. 引导方式状语从句,作“正如,好象,按照”解。主要的句式有as if(as though);just as;just as…as .
① When at Rome, do as Romans do. ② We do farm work as the old peasant teaches us. ③ When a pencil is partly in a glass of water, it looks as if it were broken. ★④ As(it is)in your country, we grow wheat in the north and rice in the south. 正如(像) 你们国家一样,……。
4. 引导条件状语从句。主要句式有:
as long as /so long as 只要
As long as you study hard, you will make great progress.
5. 引导让步状语从句;作“虽然,尽管”解。这时从句常用倒状语序,即把从句中的表语,状语或动词原形放在as之前。
① Child as she is, she knows a lot. ★→ Though she is a child, she knows a lot.
② Busy as he is, he insists on studying. → Though he is busy, he ….
③ Try as he might, Tom could not get out of the difficulties. → Though he might try, Tom could not get out of the difficulties.
Ⅲ. As作关系代词
1.
引导限制性定语从句,用在“such… as”, “the same …as/the same as”“so/as…as”等结构中,
He wished to be such a man as Lei Feng was.
The teacher gave the students so difficult a problem ___ no one could work out.
He is not the same man ___ he used to be.
①
②
2. 引导非限制性定语从句,用来指代它前面的整个句子(即先行句),意思是“这一点”。这个分句可以放在句首,句中,或句末。
③
This elephant is like a snake, as anybody can see.
④
As is well known, oceans cover more than 70% of the earth.
3.
若非限制性定语从句位于句首,句中或句末, 则用as来引导。
As we expected, pleted his task with great ess.
①
②
pass was invented in China, as we know now.
4.
若非限制性定语从句中的谓语动词是 be said, be known,be expected, be reported , be announced等结构时,不论是在句首,句中, 句末,都必须as