but for要不是,本身就含有对于已发生的事情的一种假设,所以表示的是过去的某一个状态举个例子:But for his help,i couldn't have made such big progress.要不是他的帮助,我不会取得如此大的进步!
给你一个公式(基本上是这样):虚拟语气里,表示对现在虚拟的时候,主句谓语动词do变did,从句变would do;表示对过去已发生的虚拟是,主句变have done从句变would have done(注,有时would可用could、might、should等词语代替。
But for you, they might have given us the slip.
要不是你,我们可能已经被他们甩掉了。
I'm changing my email address but for the meantime you can use the old one.
我要更换电邮地址,不过那个旧的暂时也还可以用。
I was sure she knew the answer but for some reason she hung back.
我敢保证她知道答案,但不知为什么她不敢说出来。
There's still another ten minutes of the game to go, but for practical purposes it's already over.
比赛虽然还有十分钟,但实际上等于已经结束了。