時(shí)間狀語(yǔ)從句
時(shí)間狀語(yǔ)從句常用的連詞有：when,as,while,before,after,since,till,until,as soon as,once.
【例】
Before I could get in a word,he already gave orders.
我還來(lái)不及插話,他已經(jīng)吩咐下去了.
After the students were all in the lab,the professor brought out three bottles.
在學(xué)生們?nèi)M(jìn)入實(shí)驗(yàn)室后,教授拿出三個(gè)瓶子來(lái).
學(xué)習(xí)時(shí)間狀語(yǔ)從句應(yīng)注意以下幾點(diǎn)：
（1）時(shí)間狀語(yǔ)從句中一般不使用將來(lái)時(shí)態(tài),盡管主句使用將來(lái)時(shí)態(tài),一般使用一般現(xiàn)在時(shí)態(tài)或現(xiàn)在完成時(shí)態(tài).
【例】
I'll go on with the work when I come back tomorrow.
我明天回來(lái),我將繼續(xù)做這項(xiàng)工作.
Please tell him about it when you see him back.
你看到他回來(lái),就告訴他這件事.
（2）till/until引導(dǎo)時(shí)間狀語(yǔ)從句,主句的謂語(yǔ)動(dòng)詞如是延續(xù)動(dòng)詞,可使用否定或不用否定,如果是不延續(xù)動(dòng)詞,必須使用否定形式.
【例】
He didn't go to bed until it was 12 o'clock last night.
他昨晚十二點(diǎn)才上床睡覺(jué).
They worked until it was dark.
他們一直工作到天黑.
（3）as soon as,the moment,every time,each time,the minute,the instant,the day,the week,the year,the first time,next time,any time,the last time,all the time,from the time,by the time,immediately,instantly,directly等表示時(shí)間的詞語(yǔ),后面也可以接時(shí)間狀語(yǔ)從句,表示“一……就……”.
【例】
I recognized you the minute I saw you.
我一見(jiàn)到你,就認(rèn)出了你.
By the time he was fourteen,he had built his own lab.
到他十四歲的時(shí)候,他已建起自己的實(shí)驗(yàn)室.
（4）主句使用過(guò)去進(jìn)行時(shí)或過(guò)去完成時(shí),或是was/were about to do Sth.,后面從句使用when從句,而且謂語(yǔ)動(dòng)詞使用一般過(guò)去時(shí),這時(shí)when不當(dāng)“當(dāng)……時(shí)候”解,而當(dāng)“突然”解.
【例】
They were working in the fields when it began to rain.
他們?cè)诘乩镎芍顣r(shí),天突然下起雨來(lái).
He was about to leave when the telephone rang.
他剛要走,突然電話鈴響了.