as作連詞的用法:
1.作“在-------期間,當(dāng)----的時(shí)候”引導(dǎo)時(shí)間狀語從句.注意與when、 while的用法區(qū)別.
①下列情形時(shí),只用as,而不用when或while.
1)用于表示同一個人的兩種動作交替進(jìn)行,指一邊----一邊.如:
The girl sings as she goes to school.
He looked behind occasionally as he went forward in the forest.
2)表示兩個同步發(fā)生的動作或行為,意思是隨著-----的發(fā)展.如:
As time went on / by,she became more and more beautiful .
As children get older,they become more and more interested in everything.
3)表示兩個短暫行為或事情幾乎同時(shí)發(fā)生.如:I watched her as she read the book.
I thought of it just as you opened your mouth.
Just as the flying worm hit her face,she gave a loud cry.
4)接在名詞后面表示某一個年齡段時(shí).如:
As a young man,he was active in sports.
②when作"當(dāng)……的時(shí)候"解,可以指較短的(一點(diǎn))時(shí)間,也可指一段時(shí)間.如:When I was at college,I could speak several foreign languages.When the clock struck twelve,I had slept for 2hours.
③ while常表示一段較長的時(shí)間或一個過程,強(qiáng)調(diào)主句謂語動詞與從句謂語動詞同時(shí)發(fā)生.如:Work while you work.Play while you play.