30 時間狀語從句　Track 030

（1）時間狀語從句要用一般現(xiàn)在時表示將來動作
a. I’ll speak to him when he arrives.
不說…when he will arrive.*
b. I’ll tell him about it when he comes back.
不說…when he will come back.*
（2）when
when的意思相當于at that time（在……時刻），從句的謂語動詞通常是短暫性動詞，表示瞬時的動作。注意主句和從句的時態(tài)。
例句
a. I’ll speak to him when he arrives.
b. I’ll tell him about it when he comes back .
c. When I arrived, he was talking on the phone.
我到的時候，他正在打電話。
d. When I got there, he had already left.
我到那兒的時候，他已經(jīng)走了。
e. When I got there, he was leaving the office.
我到的時候，他正準備離開辦公室。
從句的謂語也可用延續(xù)性動詞，這時從句往往用過去進行時態(tài)，表示過去某一時間正在發(fā)生的動作。例如：
f.The doorbell rang when I was telephoning.
（3）while
while的意思相當于during that time（在……期間），表示某一時間段內(nèi)發(fā)生的動作。因此，從句謂語通常只用延續(xù)性動詞。
例句
a. The phone rang while I was taking my bath.
b. The doorbell rang while we were watching TV.
c. A detective（偵探） arrested a criminal and was about to handcuff（上手銬） him when a huge gust（一陣狂風） of wind blew off the detective’s hat.
“Shall I go and fetch it?” the criminal asked.
“Do you take me for a fool?” asked the detective. “You wait here while I go and get it!”（此句中go and get雖然是短暫性動詞，但兩個動詞連用表示的是一段時間內(nèi)的活動。）
（4）until
1） 當主句謂語動詞是延續(xù)性動詞時，主句通常用肯定形式。例如：
a. Wait until he comes back. （wait為延續(xù)性動詞）
b. We’ll stay here till it stops raining. （stay為延續(xù)性動詞）
c. Until I came back, he had been waiting for me at my home.
2）若主句謂語動詞是短暫性動詞，則主句要用否定形式。這就是我們常說的“not…until…（直到……才……）”結構。
例句
a. I did not realize how special my mother was until I became an adult.
直到我長大成人以后，我才懂得母親是多么不平凡。
b. Ice cream did not reach America until about the middle of the eighteenth century.
c. I didn’t go to bed until 12 o’clock last night.
我昨晚直到12點鐘才睡覺。
d. He didn’t leave the office until his boss came back.
直到老板回來之后他才離開辦公室。
3）我們還可以把not…until轉(zhuǎn)換成倒裝句型：
a. Not until 12 o’clock last night did I go to bed.
b. Not until his boss came back did he leave the office.
可見，當Not until提前至句首時，主句用部分倒裝。
（5）表示“一……就……”的連詞
表示“一……就……”的連詞有：as soon as, once, immediately,the moment。這些連詞后通常接短暫性動詞，表示瞬間動作。注意分析下列句子：
a. We will leave as soon as it stops raining.
雨一停，我們就動身離開。
b. Once it stops raining, we will leave.
c. It began to rain as soon as I arrived home.
我剛到家，天就下起雨來。
d. It began to rain immediately I arrived home.
e. It began to rain the moment I arrived home.
（6）by the time
by the time的意思是“當……時候”，強調(diào)的是“一個動作在另外一個動作發(fā)生時已經(jīng)完成”。因此，與by the time從句搭配的主句要用完成時態(tài)。注意下句時態(tài)搭配：