③让步状语从句
让步状语从句指事实时，从句谓语动词用陈述语气。若从句内容表示现在和将来的假设情况，从句谓语动词用虚拟语气。
Though he (should) fail, there would still be hope.即使他失败了，仍有一线希望。
I should say the same thing even if he were here.即使他在这里，我还是要这么说。
Whether he (should) succeed or fail, we shall have to do our part.不管他成功还是失败，我们还是要做好自己的事。
However hard it might rain rains, we shall go there together.不管雨下得多么大，今晚我们还是要去那里。
No matter what his social position (might) be, a man is equal in the eye
of the law.一个人不论其社会地位如何，在法律面前都是平等的。
C．定语从句中的虚拟语气
在It is (high) time (that) ...结构中，定语从句的谓语动词用过去式，表示“到某人该做某事的时间了”。
It is time that the children went to bed.到孩子们睡觉的时间了。
It is high time that we began the meeting.正是我们开会的时间了。
四、其他句型中的虚拟语气
A．If only......
If only位于句首引起的感叹句用虚拟语气，动词用一般过去时表示目前的愿望，用过去完成时表示过去的愿望，用would或could表示将来。
If only he knew the answer.他要是知道答案就好了。（用过去时表示现在）
If only I could speak several foreign languages！我要是能讲几种外语就好了！（用wouldcould表示将来）
If only you had told me the truth before. 要是你以前告诉我真相就好了。（用过去完成时表示过去）
注意：if only和wish的用法相同，表示的意愿也基本相同。
If only it would rain.但愿天能下点儿雨！= How I wish it would rain.
If only I had known her earlier!要是我早点儿认识她就好了！= I
wish I had known her earlier.
B．would rather
would rather, would prefer, would sooner等后接从句，表示“宁愿”，动词用过去时表示当时和将来的情况，用过去完成时表示过去的情况。
I would rather you left today.我宁可你今天走。
I would prefer he didn't stay here too long.我倒希望他不要在这儿呆得太久。
I would rather I hadn't seen that film yesterday.我宁愿昨天没有看那场电影。
提示：
would rather主要有两种用法。
1．后接不带to的不定式
I'd rather play tennis than swim.我宁愿打网球，也不愿游泳。
I'd rather not go to the movies.我宁愿不去看电影。
Which would you rather have, tea or coffee你喜欢喝茶，还是咖啡
2．后接不用连词的that从句
I'd rather you went home now.我希望你现在就回家。
I would rather my daughter attended a public school.我希望我的女儿能上公立学校。
C．表示愿望的感叹句
在表示祝愿的感叹句中，用动词原形，表示愿望。
Long live the People's Republic of China!中华人民共和国万岁！
May you be happy!祝您快乐！
God bless you!上帝保佑你！
Success attend you!祝你成功！
The Lord save us!愿主救我们！
D．情态动词用于虚拟语气
部分情态动词的过去形式（could, might, should, would），可以用于非真实条件句以及其他结构中表示虚拟语气。
1．表示想像或猜测
If I could speak French, I would teach you.如果我会说法语，我就能教你。（我不会，所以不能教你）
If you phoned him right now, you might get the matter settled.如果你现在给他打电话，你就可以把问题解决了。
There could be something wrong with the tape recorder.这台录音机可能出毛病了。
He might have said so.他可能这样说过。
Could he have done such a foolish thing他会做这样的傻事吗？
2．表示委婉或客气
虚拟语气（could, would, might +动词原形）可使说话者的口气变得委婉客气。
You could answer this email for me.你可以替我回这个电子邮件。
Could you leave me your telephone number and address你能将电话号码和地址留给我吗？
Would you mind opening the window劳驾把窗子打开，好吗？
You might as well put off the discussion till next week.你们不妨把讨论推迟到下个星期。
比较：
would lide to do
愿意，想要
would lide to have done
本来想
I would like (to have) a word with you.我想和你谈一谈。(现在想)
I would like to have talked with you.我原本想和你谈一谈的。（没有谈成）
3．表示惋惜或责备
Given more time, we could have done better.如果给我们更多时间，我们能够干得更好些。（我们并没有得到更多的时间）
You could have got up a little earlier！你完全可以早点儿起来！（实际上没有早起）
It was cold yesterday. I should have worn a heavy coat.昨天很冷，我该穿件厚外套的。（但我没穿）
This wall shouldn't have been pained blue.这墙不应该漆成蓝色。（但已漆了）
提示：
当代英语一个显著的变化就是虚拟语气的使用越来越少，许多该用虚拟语气的地方都用陈述语气代替。
He suggested that I went to the hospital at once.他建议我们立刻去医院。（原应用should go）
We shall write down the address lest we forget.我们要把地址记下来，以免忘记。（原应用should forget）
Imagine you are an astronaut.设想你是个宇航员。（原应用were）
情态动词