時(shí)間狀語從句是英語職稱英語考試常考的語法知識(shí)點(diǎn)之一，為了幫助考生在考前能夠掌握時(shí)間狀語從句的引導(dǎo)詞及其用法，網(wǎng)校小編整理了這篇職稱英語考試語法考點(diǎn)，希望可以幫到大家！

when while as after before as soon as since till /until by the time 在時(shí)間狀語從句中，要注意時(shí)態(tài)一致。一般情況下主句是將來時(shí)的時(shí)候，從句要用一般現(xiàn)在時(shí)。

when,while和as的區(qū)別

when引導(dǎo)的從句的謂語動(dòng)詞可以是延續(xù)性的動(dòng)詞，又可以是瞬時(shí)動(dòng)詞。

when有時(shí)表示“就在那時(shí)”，when=and then； at that moment （正在那個(gè)時(shí)候）； 還可以表示從句動(dòng)詞的動(dòng)作在主句動(dòng)詞的動(dòng)作“之前 ”或“之后”發(fā)生。有很多情況已經(jīng)約定俗成，可以當(dāng)成句型來記憶。例如：

be going to do …… when ……did ……

be about to do…… when…… didi……

be on the point of doing…… when ……did……

be starting to do…… when …… did……

be doing…… when …… did……

had just done……when…… did……

had hardly done……when……did……

had scarcely done……when……did……

had no sooner done…… when…… did……

When she came in,I stopped eating. （瞬時(shí)動(dòng)詞）

When I lived in the countryside,I used to carry some water for him.（延續(xù)性的動(dòng)詞）

We were about to leave when he came in.

When I had read the article,he called me. （ 從句動(dòng)作發(fā)生在主句之前，注意時(shí)態(tài)表達(dá)，只能用when ）

When I got to the cinema,the film had begun. （從句的動(dòng)作發(fā)生在主句之后，只能用when，并要注意時(shí)態(tài)）

He was about to leave,when the telephone rang. （ 此時(shí)不能放在句首。主句動(dòng)詞一般表達(dá) “正在” “即將”。at the moment/and then）