I wouldn't mess with him if I were you.

我要是你就会离他远点儿。

《牛津词典》

I'd have nothing to do with him, if I were you.

如果我是你，我就不会跟他有任何瓜葛。

《牛津词典》

I told him if he withdrew it was on his own account.

我告诉他，如果他退出那么他要自负其则。

《柯林斯英汉双解大词典》

I added that if Mister Wheeler could tell me anything about this Leonidas W.Smiley, I would feel a great responsibility to him.

VOA: special.2009.08.29

I'm coming at this guy and what I want to do, if I can, I want to kill him.

我面对这个家伙,我该怎么做,如果我可以,我就杀了他

耶鲁公开课 - 古希腊历史简介课程节选

where if I have any questions on any subject, I can just walk in and ask him and he'll,

这样的话，如果我对任何事情有什么问题，我就可以直接走进来问他，

有印象的教授 - SpeakingMax英语口语达人

And if I were him I would, too.

FORBES: The NRA's Communications Crisis

Before we'd even ordered, I asked him if I could get his opinion on something personal, but told him I would only feel comfortable sharing if he would then tell me something about himself.

WSJ: Advice for Making New Friends: Share But Don't Overshare

"You put your trust in doctors who you think know best but now I feel as if I murdered him because I might have done more, " she said.

BBC: Paul Ghuman