1.将条件句隐含在介词短语中
But for your help we couldn’t have succeeded in the experiment.
（=If it hadn’t been for your help）
如果没有你的帮助，我们的实验是不会成功的。
Without air，no one could live.
（=If there were no air）如果没有空气，谁都不能活。
In different circumstances，I would have said yes.
（=If circumstances had been different）如果情况有所不同，我就会同意了。
With favorable winds，we might have gotten there in two days.
（=If there were favorable winds）如果那时候顺风的话，我们两天就能抵达那儿了。
2.将条件句隐含在某些连词中
I didn’t know that he was a cheat，or else I wouldn’t have believed him.
（or else=if I had known he was a cheat）
我不知道他是个骗子，不然我也不会相信他了。
I’m really very busy，otherwise I would certainly go there with you.
（otherwise=if I were not so busy）
我真的是太忙了，不然我就会同你一道去了。
3.将条件句隐含在定语从句中
A man who would succeed should do his best.
（=If a man should do his best）一个人想成功，必须尽其全力。
Anyone who had seen that painting might have taken it for a photo.
（=If anyone had seen that painting）
凡是看过那画的人，都可能把它看成是照片。
4.将条件句隐含在一定的上下文中
I would write to her，but I don’t know her address.
（=If I knew her address）
我会给她写信的，就是不知道她的地址。
Don’t bother to read all these papers.It would take too long.
（=If you read all these papers）
不要费事看所有这些文件了，那会花太多时间。