英语中有许多词和短语可用以引导时间状语从句，表示“一……就……”，它们虽不是连词，但具有连词的功能。这些词归纳起来，主要有以下几类：
一、名词类
这类词主要有the moment, the minute, the second, the instant, the day 等。如：
The moment I saw him I knew there was no hope. 我一看到他就知道没希望了。
The instant he opened the door he saw the thief. 他一开门就看见了这个贼。
He is going to visit his aunt the day he arrives in Beijing. 他一到北京，就去看他姨妈。
二、副词类
这类词主要有immediately, directly, instantly, once 等。如：
Once he arrives, we can start. 他一来我们就可以开始。
Immediately he came I told him the news. 他一来我就把消息告诉了他。
三、句型类
这类词主要有no sooner…than, hardly…when等。如：
We had no sooner set out than it began to rain. 我们刚出发就下雨了。
She had hardly arrived when it began to snow. 她刚到就下起雪来了。
注：若将 no sooner, hardly 置于句首，则其后要用倒装语序。如：
We had no sooner reached the airport than the plane took off.=No sooner had we reached the airport than the plane took off. 我们刚到机场，飞机就起飞了。