if

I'll pay you double if you get the work finished by Friday.

如果你周五前完工，我付你双倍的报酬。

We'll have the party in the garden if the weather's good. If not (= if the weather is not good), it'll have to be inside.

如果天气好的话，我们将在花园里开派对。如果不好，就只好在室内了。

If anyone calls, just say I'll be back in the office at four o'clock.

要是有人给我打电话，请告诉他们我4点钟回办公室。

If she hadn't called, I wouldn't have known.

要不是她打来电话，我还不知道呢。

I wouldn't work for them (even) if they paid me twice my current salary.

即使他们付给我的工资是现在的两倍，我也不会为他们干活。

We'll deal with that problem if and when it arises.

等到那个问题出现我们再处理。

If disturbed, the bird may abandon the nest, leaving the chicks to die.

如果受到惊扰，鸟可能会弃巢而去，留下雏鸟，任由它们死亡。

They're great kids, even if they can be demanding.

虽然他们要求多多，但他们是很好的孩子。

It was a hot, if windy day.

那天虽然有风，却依然很热。

If water is heated to 100°C it turns to steam.

水被加热到100摄氏度时，就会变成蒸汽。

If I don't get enough sleep I get a headache.

我睡眠不足时就会头疼。

I'm very sorry if I've offended you.

如果我冒犯了你的话，我很抱歉。

Mrs Kramer called half an hour ago to ask if her cake was ready.

克雷默夫人半小时前来电话问她的蛋糕做好了没有。

I don't care if he likes it or not – I'm coming!

我不在乎他乐不乐意，我反正要来！

I was wondering if you'd like to come to the cinema with me this evening?

不知你今晚想不想与我一起去看电影？

If you'd like to take a seat, Mr Chang will be with you in a moment.

您请先坐一会儿吧，张先生一会儿就过来。

Would you mind if I open/opened (= can I open) the window?

我开窗您介意吗？

There are, if you don't mind me saying so, one or two problems with this plan.

恕我冒昧，我觉得这个计划有一两处问题。

There's a big if hanging over the project (= it is uncertain whether the project will happen).

这个计划能否启动仍然悬而未决。