如果她早知道，她就不会发脾气了。

If she had known she would not have snapped.

youdao

如果我早知道这些，我是不会做这件事的。

If I'd known then I would not do it.

youdao

如果我早知道会发生这种事，我上学期就会选这门课了。

If I'd known this was going to happen, I would have taken it last semester.

youdao

And humankind receives its first set of explicit laws, no more implicit, "Murder is bad." "Oh I wish I had known!"

人类要接受明确的律法，而非隐晦的，谋杀是不好的，哦！我要是早知道就好了“

耶鲁公开课 - 旧约导论课程节选

You should have known better.

你早该知道的。

I should have 实战 - SpeakingMax英语口语达人

Now we know that Milton was blind probably well before the time he began writing Paradise Lost, and therefore, of course, he was then unable to read.

现在我们知道弥尔顿很可能失明了,这早于他开始写《失乐园》的时间，因此，他不能通过眼睛阅读。

耶鲁公开课 - 弥尔顿课程节选