英語四級備考知識之as的用法

as可以作連詞、介詞及關係代詞。在英語四級考試中經常會用到，現在，小編現將其用法小結如下，大家可以作爲參考。

一、 as作連詞的用法:

1. 作"當……的時候",引導時間狀語從句。注意與when、 while的用法區別。

① when作"當……的時候"解,可以指較短的(一點)時間,也可指一段時間。如:

When he was at college, he could speak several foreign languages.

When the clock struck twelve, all the lights in the street went out.

② while常表示一段較長的時間或一個過程,強調主句謂語動詞與從句謂語動詞同時發生。如:

Work while you work. Play while you play.

③ 但屬下列情形時,只用as, 而不用when或while。

A) 用於表示同一個人的兩種動作交替進行,指"一邊……,一邊……"。如:

The girl dances as she sings on the stage.

He looked behind from time to time as he went forward.

B)表示兩個同步發展的動作或行爲,譯爲"隨着……"。如:

As time went on / by, she became more and more worried.

As children get older, they become more and more interested in the things around them.

C)表示兩個短促行爲或事件幾乎同時發生。如:

I thought of it just as you opened your mouth.

Just as the flying worm hit her face, she gave a loud cry.

D) 後接名詞表示某一年齡段時,用as。如:

As a young man, he was active in sports.

2. as=since, 作"既然"、"由於"解,引導原因狀語從句,常用來表示已爲人們所知或顯而易見的原因或理由。如:

As / Since you''''re not feeling well, you may stay at home.

As he wasn''''t ready in time, we went without him.

3. as=in the way that, 作"像"、"按照……的方式"解,引導方式狀語從句。如:

He speaks English as Americans do.

Remember, you must do everything as I do.

4. 用於as...as...或not so/ as...as...中,前一個as是副詞,後一個as是連詞,引導比較狀語從句。如:

They helped the old man as often as possible.

I don''''t speak English so/ as well as he does.

5. 作"雖然"、"儘管"解,引導讓步狀語從句。常用倒裝語序,即adj. /adv. / n.+as +主語+謂語+主句。如:

Tired as they were, they walked on.

Child as he is, he knows a lot. (child前不用冠詞)

以上就是內容就是關於英語四級語法知識，希望可以給大家在備考的時候帶來幫助。