摘要：If the report has been done already, why haven't you told me?

英语语法"需要总结，否则就成了碎片化，容易混淆…。

IF~可引出条件从句，它可用于什么时态？简述如下：

1/ ‌用于"一般现在时‌"：

If you have talent and good looks, you could become a movie star.

如果你有才有貌，你有可能会成为电影明星。

If you want to buy a house, you must make a "down payment" first.

如果你想买楼，你必须先付"首付"。(规则)。

2/用于"一般现在进行时"：

if you are travelling North, you must change trains at "Leeds".

如你去北方旅行，你须在"利兹"换乘火车。

If I'm overstating the importance of nutrition, at least it will lead to the woman taking charge of her own symptoms...

即便我夸大了营养的重要性，至少会使得这个女士知道关心自己的症状了…

3/用于"一般过去时‌"：

He acted as if he was certain of success.

他的举止好像是个成功人士。

If you lost your way, you would have to ask a policeman.

4/用于"一般过去进行时"：

Nobody could say if she was laughing or crying.

没人知道她是哭还是哭。

He points two fingers at his head, as if he were holding a gun...

他把两个手指指着他的头，好像是举着一把手枪…

5/ 用于"一般将来时"：

If you will help me tomorrow, I will be very grateful.

If you will sit down for a few moments, I'll tell the manager you're here.

如你愿意在此坐一会儿，我将告诉老板你来了。

6/ 用于"将来进行时‌"：

If you will be studying when I arrive tomorrow morning, I'll wait outside.

如明天上午我到时你正在学习，我就在外面等。

7/ ‌用于"现在完成时‌"：

If you have finished your homework, you can go out to play.

如你完成了作业，你可以出去玩会儿。

If you have lost your keys, you will not be able to get into the house.

如你丢了钥匙，你就没法进屋了。

8/ 用于"现在完成进行时‌"：

If you have been studying all day, you must be tired now.

如你一整天都在学习，你现在一定很累。

9/‌可用于"过去完成时‌"：

If she had finished her work earlier, she wouldn't have missed the bus.

如果她早点完成工作，她就不会错过公交车了。

10/ 用于"过去完成进行时‌"：

If he had been studying harder before the exam, he might have passed it.

如果他在考试前学习更努力一些，他可能就通过了。

11/ 可与"情态助动词连用"：

If I may make a suggestion, perhaps we could begin a little earlier next week.

如果我提建议，我们下个星期应早点开始。

If you would care to leave your name, we'll contact you as soon as possible.

如你愿意留下你的名字，我们将尽快联系你。

12/可用于"被动语态"

A/一般现在时被动

If you are accepted for this post, you will be informed by next week.

如果你被这个职位录用，下周就会通知你。

B/‌过去完成时的被动：

If the project had been completed on time, we wouldn't be in this mess.

如果项目能按时完成，我们就不会陷入这种困境。

If the documents had been reviewed by the lawyer, we wouldn't have made this mistake.

如果文件已经被律师审核过，我们就不会犯这个错误了。

C/‌一般将来时的被动

If the report is to be finished tomorrow, we could present it to the client.

如果报告明天能完成，我们就可以把它交给客户了。

D/‌现在完成时的被动：

If the report has been done already, why haven't you told me?

如报告早已完成，你为什么不告诉我？

13/可跟用There be：

If there is sufficient sea room, altering the ship's course to avoid collision may be the best way.《避碰规则》择句。

如果海域足够宽阔，改变航向以避免碰撞可能是最佳方案。

If there had been enough time, we could have done it better.

如果有足够的时间，我们会做得更好。

14/ 可用于"虚拟语气"

A/对"现在虚拟"：

If I had a time machine, I would go back to the past.

如果我有时光机器，我就会回到过去。

B/对"过去虚拟"：

If I had studied harder, I would have passed the exam.

如果我当时学习更努力，我就会通过考试。

C/对"将来虚拟"

If you should succeed in the future, everybody would say you're fortunate.

如果你将来成功了，人人都会说你命好。

总结：

IF~从句几乎可用于任何时态，只要与主句时态匹配，即可大胆使用。

个人观点、仅供参考。

来源：鲲鹏展翅