A 时间从句由下列表示时间的连词来引导：
after immediately1 till／until
as nosoonerthan when
as soon as since whenever
before the sooner while
hardlywhen
时间从句也可由the minute，the moment来引导。
用when，as，while的例句，参见第331节至第333节。
用before的例句，参见第195节B。
B 请注意，时间从句中不需要以后时态或条件时态。
1 如将下列以后时态放入时间从句中，须将它变为一般时态。
一般以后时：
Youll be back soon．Ill stay till then．
你会非常快回来，我一直等到那时。等于：
Ill stay till you get back．
我一直等到你回来。
be going to形式：
The parachutist is going to jump．Soon after he jumps his parachute2 will open．
跳伞运动员要往下跳。他刚跳之后不久，降落伞就会打开。
目前进行时用做一般以后时和以后进行时：
Hes arriving／Hell be arriving at six．
他将在6点到。
但：
When he arrives hell tell us all about the match．
等他到了，他会好好给大家讲讲那场比赛。
Before he arrives Ill give the children their tea．
在他来到之前，我会给孩子们吃茶点的。
如进行时态表示某一行动在继续，则其完全可以用在表示时间的从句中：
Peter and John will be playing／are playing／are going to play tennis tonight．While they are playing（during this time）well go to the beach．
今晚彼得和约翰要去打网球。他们打球时，大家将去海滨。
2 在时间从句中，以后完成时变为目前完成时，以后完成进行时变为目前完成进行时：
Ill have finished in the bathroom in a few minutes．
我一会儿就用完浴室了。
The moment／As soon as I have finished Ill give you a call．
我一完事儿，就给你打电话。
3 在时间从句中，条件时态变为过去时态：
We knew that he would arrive／would be arriving about six．
大家了解他将在六点钟左右到。
We knew that till he arrived nothing would be done．
大家了解在他到来之前，什么都干不了。
但，如when引导的是一个名词从句，后面可跟以后时态或条件时态：
He said，When will the train get in？
他说：火车什么时间进站？等于：
He asked when the train would get in．
他问火车什么时间进站。
C since从句（参见第187与第188节）
since从句后面常跟完成时态（另参见第188节）：
Theyve moved house twice since they got married3．／Since they gotmarried，theyve moved house twice．
他们结结婚以后已搬了两次家。
He said hed lived in a tent since his house burnt down．
他说自从他的房子被烧毁后，他就一直住在帐篷里。
Its ages since I sailed4／have sailed a boat．
我未驾驶帆船已有好多年了。
I havent sailed a boat since I left college．
自从我大学毕业后就没再驾驶帆船了。
D after从句
after从句之后常跟完成时态：
After／When he had rung off I remembered
等他把电话挂断了之后，我才想起
After／When youve finished with it，hang it up．
你用完了之后，请把它挂起来。
E hardly／scarcely when，no sooner than（另参见第45节）：
The performance had hardly begun when the lights went out．
Hardly had the performance begun when the lights went out．
演出最初就停电了。
这里可以用scarcely代替hardly，但不容易见到。
He had no sooner drunk5 the coffee than he began to feel drowsy6．
No sooner had he drunk the coffee than he began to feel drowsy．
他喝了咖啡没多一会儿，就犯困了。
He no sooner earns any money than he spends it．
Immediately he earns any money he spends it．
他钱一挣到手，就花光了。
注意the soonerthe sooner的使用方法：
The sooner we start，the sooner well be there．
大家动身得越早，到那儿就越早。
