二、虚拟语气在条件句中的用法

1.条件句分类

条件句指表示假定情况的句子。这类句子大多数都包含一个由 if 引起的条件从句，少数条件从句由 unless、suppose 等引起。条件句有两种：

（1）真实条件句（sentences of real condition）：

一种表示可能成为现实的情况，称为真实条件句。在这些句子中假设的情况都是可能发生的，句中谓语都使用陈述语气，如：

If you ever touch me again, I'll scream.

She's taking a stick with her in case she has any trouble on the way.

（2）虚拟条件句（sentences of unreal condition）：

与上述情况相反，如果假设的情况纯然是假想，是与现实不一样的或发生的可能性不大的，这种句子就叫作虚拟条件句，这类句子中的谓语形式称为虚拟语气，如：

If I were you, I'd go to night school.

If you had listened to me, you wouldn't have made so many mistakes.

2.表示现在或将来情况的虚拟条件句

表示现在或将来情况的虚拟条件句，动词的形式可以用下表表示：

（1）一般情况下，条件从句多表示一个假想的与事实相反的情况，或不太可能发生的情况：

If we had enough money, we would buy a computer.

If you didn't stay up so late every evening, you wouldn't feel so sleepy in the morning.

① 在条件从句中，如果谓语动词是 be，一般要用 were，特别是在较正式的文体中：

If there were anything to tell, I would tell it to you.

If she were trying harder, her parents wouldn't be so anxious.

② 但在口语中，在第一、三人称后，也有人用 was：

I wouldn't think a minute if I was you.

If John was here, he would know.

不过在第一人称后还是用were较好，特别是在if I were you (in your position)中：

If I were you, I'd take that job.

If I were in your position, I would accept their offer.

（2）在主句中有时可用 could 或 might 构成谓语：

If he knew the facts, he could tell us what to do.

If Jane tried harder, she might do better.

有时还可用 should 或 ought to：

If he failed, he ought to (should) try again.

（3）从句中有时也可能用 were to 或 was to 构成谓语，表示将来万一发生的情况：

If you were to speak to him, it would carry more weight.

You'd be the first to be sorry if anything was to happen to him.

从句中有时可用 would，表示“愿意”：

If Ann would admit this, I shouldn't quarrel with her.

I should be glad if you would give me an account of it.

（4）从句中可能用 should 构成谓语，这时主句可以用虚拟语气，也可以用陈述语气：

If we should fail in this, we are (would be) ruined.

If a serious crisis should arise , the public would have to be informed of its full implications.

（5）if 可能被省略，这时从句要用倒装语序：

Were she here, she would support the motion.

Should you change your mind, no one would blame you.

（6）从句有时可用“If it were not for...”这种句型，表示“若不是……”：

If it weren't for your help, I would still be homeless.

if 有时可以省略（后面要用倒装语序）：

Were it not for your help, I wouldn't be doing so well.

（7）在极少数情况下，从句中的谓语可用动词原形表示（主句谓语可用陈述语气）：

If any person be found guilty, he shall have the right of appeal.

If that be the official view, it cannot be accepted .

（8）还有一些特殊的不完整的条件句也可能用虚拟语气：

Imagine your child played truant.

Without me to supplement your income, you wouldn't be able to manage it.

3.表示过去情况的虚拟条件句

这类句子中的谓语动词形式可以用下表表示：

（1）这类从句表示一个与事实完全相反的过去情况（“'d”是 had 或 would 的紧缩形式）：

If I had worked harder at school, I' d have got a better job.

The view was wonderful.If I' d had a camera, I would have taken some photographs.

（2）主句中可以用 could、might 或 should 构成谓语：

I could have earned something if I had meant to.

If the weather hadn't been so bad, we might have gone out.

If he had received the present, he should have thanked her.

（3）从句中有时可用 lf it had not been for 及倒装式的“Had it not been for”构成谓语，表示“要不是有”：

If it hadn't been for Margaret, I might not have understood.

If it hadn't been for the rain, we would have had a good harvest.

（4）可把从句改为倒装结构而省略 if：

Had I known your address, I would have written before.

Had I not seen it with my own eyes, I would not have believed it.

4.一些特殊的虚拟条件句

（1）错综时间条件句（conditional sentences of mixed time）：

① 有时会有一些特殊情况，如：

If I had not got married, I would still have been living abroad.

If she were trying harder, her parents wouldn't be so anxious.

② 有时主句谓语和从句谓语表示的动作发生的时间不同，如：

If you'd listened to me, you wouldn't be in such trouble now.

If he had received six more votes, he would be our chairman now.

（2）含蓄条件句（sentences of implied condition）：

① 在不少情况下，句子不一定包含一个条件从句，但意思却和条件句差不多，这时谓语仍可以用虚拟语气：

But for his pension, he would starve. （=Were it not for his pension...）

Without your help, I couldn't have achieved all this. （=Had it not been for your help...）

I would have written before, but I have been ill.

② 这种含蓄条件句在日常口语中是很常见的，也很有用，如：

情态动词，特别是 should、would、could、might，在日常口语中用得很多，使句子显得比较委婉：

Would you like some tea? —Thanks, but I'd prefer coffee if there is any.

Could I borrow your thermos?

试比较下面句子：

I think you're right. （陈述语气）

I should think that might be a good solution. （接近虚拟语气）

I want you to collaborate with us. （陈述语气）

I should (would) like you to collaborate with us. （接近虚拟语气） sotnTEB2d2A4Uldpj9ZO+qabes1iB4rlhriR/eYkNbxKyqMula1dkD4sI+15jKfc