谁能简洁一点告诉我虚拟语气的用法呢？

Question

通俗易懂……

Answer 1

虚拟语气中分if 条件句中的虚拟语气和固定句式中的虚拟语气
一.if 条件句中的虚拟语气

If 从句 主句
1.与现在事实相反 过去式 (be--were) Would/should/could+ 动词原形
2.与过去事实相反 过去完成式 Would/should/could+ 现在完成时
3.与将来事实相反 Were to do
should do Would/should/could+ 动词原形

4. 交叉虚拟 （即时间状语混合）

有时候,条件从句表示的动作和主句表示的动作,发生的时间是不一致的(如下例:一个是过去发生,一个是现在发生)

例子：if you had taken my advice yesterday, now you would be better.

IF 可以省略，引起部分倒装。 （were, should, had 提前）

5.当条件从句中出现were, should, had 等时, 可以将if 省略, 把were, should, had 放在主语的前面.

例子: Had he been here last night, I would have told him the news.

二.固定句式中的虚拟语气

suggest, demand, advise, propose 等词引导的宾语从句中

2. suggestion, proposal 引导的同位语从句中

3. It +be+ suggested /demanded + that 从句中
It is + important /necessary + that 从句中
4. For fear that (惟恐), in case, lest (以防) 引导的从句中

以上四种情况下，从句中的谓语动词是由 should + 动词原形构成， should 可以省略。

5. wish, would rather, if only, as if, as though +从句时，如果表示与现在事实相反，谓语动词用过去式；如果表示与过去事实相反，谓语动词用过去完成式。

6. It is high/ about time + 从句时，从句的谓语动词只能用过去时。

7. 介词短语可相当一个条件从句时要用虚拟语气，比如：without, but, but for, otherwise 等。But for the heavy rain we would have been there in time.

Answer 2

退时态：真实语气中的现在时变成过去时，过去时变成过去完成时，将来时变成过去将来时
1．条件句中：
 If it were not for…；If it hadn’t been for…这两种句型表示“要是没有”，相当于but for
If it had not been for the PLA man, he would not be studying English now.
 if…only…（或If only…）表示“要是…就好了”
1．名词性从句：
 demand/suugest/order/insist/propose/request/ask/advise/prefer/command/desire that…
They demanded that the aggressor troops (should) be withdrawn immediately.
由insist引导的宾语从句可以虚拟也可以不虚拟：
He insisted that he was right.坚持认为
He insisted that we should agree with him.坚持某事
由suggest引导的宾语从句可以虚拟也可以不虚拟：
His white face suggests that his not healthy.表明
He suggested that we have a rest.建议

If I could only see him once!
If only I had listened to your advice. 很明显，这种句型省略了主句
2．其他状语从句中：
 as if/as though/even if…
Tom looked sad as if he had heard bad news.
I won’t lend you any money even I had money.
3．名词性从句：
 wish that…（hope后的宾语从句不虚拟）
I wish I were as strong as you.
How I wish it wasn’t raining!
 would rather/would sooner/had rather that…表示“宁愿”
I would rather they came tomorrow.
I could go myself but I would sooner you went.
I had rather you told him than I did.
 It is time/high time that…
It is time we went to bed.
+(should) do：本回答被网友采纳