(1) Suppose/ Supposing ---  假如……

例：Suppose/Supposing he is absent, what shall we do? 假如他缺席，我们怎么办？

(2) On condition that  只要……；如果……

例：I'll come on condition that John is invited, too. 如果约翰也被邀请，我就来。

(3) provided (that)/ providing -----   只要……

例：I will come provided (that) I am well enough. 只要我身体好，我一定来。

        You may go out  providing you do your homework first. 只要你先做作业，你便可以外出。

(4) so/as long as  只要

例：As/So long as you work hard, you'll succeed in the end. 只要你好好干，终究会成功的。

(5) 祈使句 + and + 陈述句(表肯定）

例：Give him an inch and he’ll take a mile. = If you give him an inch, he’ll take a mile.  他会得寸进尺的。

(6) 祈使句+ or/otherwise +陈述句 (表否定）

例：Start at once, or / otherwise you’ll miss the train. 立即动身，否则你会错过那班火车的。

      = If you don’t start at once, you’ll miss the train.

      = Unless you start at once, you’ll miss the train.

(7) …won't...unless... 除非……否则我不会…….

例：I won't write to him unless he writes to me first. 我不会写信给他的,除非他先写给我.