5.5 不用if引导的条件从句
虚拟条件句中的条件从句除用if引导外，还可用when, unless, lest, suppose, as if, for fear, in case, on condition 等词语来引导。
The peasants prepared to feed the city when it should be freed.
农民已准备在这座城市解放后供给粮食。
Lest you should not have heard all, I shall begin at the beginning.
我怕你没有听全，所以我再从头开始讲一遍。
Unless I were well, I wouldn’t be at school.
除非我好了，否则我不会上学。
Suppose you were given a chance to study in America , would you accept?
假如给你一个到美国学习的机会，你会接受吗？（suppose 或 supposing =what if）
Supposing it were so？（=Supposing it were so，what would happen？）
要是这样的话，会怎么样呢？
He can use the bicycle on condition that he should return it tomorrow
如果明天能还回来，他就可以借用这辆自行车。
In case I forget , please remind me of my promise
如果我忘了，请提醒我的诺言。
Susan is walking slowly ,as if she were tired.
苏珊走得很慢，就像是累了似的。
与if一样，上述词语所引导的条件从句亦可用直陈语气，表可能实现或发生的事。
