Grammar: Mood & Subjunctive Mood (3)（语法：语气与虚拟语气(3)）
4. 省去从句或主句的虚拟语气：虚拟结构中的从句或主句有时形式上可以省去，但意义上仍存在。
1) 省去了条件从句的虚拟结构
That would be fine. (省略了if you should do it)
I wouldn’t have done that. (省略了if I had been given the chance)
即使给我机会的话，我也不会那样做。
2) 省去了结果主句的虚拟结构 (常表示愿望)
If only I could help you!
If only he hadn’t left.
如果他没离开该多好啊！
5. 虚拟语气的特殊用法
1) 在It is necessary (important, strange, impossible, impractical, advisable, natural … 等表示主观看法的形容词) that …这类句型里, that 引导的从句里，谓语动词 用should + 动词原形，should 常省略。
It is advisable that he travel abroad.
It was necessary that the question be settled at once.
It was strange that he should have gone away without telling us.
他没告诉我们一声就离开了，这有点奇怪。
2) 虚拟语气用在宾语从句中。
a. 用于动词wish后的宾语从句中，表示不可实现的愿望，或对过去事情的遗憾。
I wish I hadn’t been so forgetful. Then I wouldn’t have missed the lecture.
I wish I knew how to design a robot, but I don’t.
I wish I hadn’t said that.
我真希望我没说过那话。
b. 用于动词demand, require, suggest, propose, order, command, insist, urge, advise, desire 等后的宾语从句中，从句用should + 动词原形，should常省略。
Most students insist that the English teacher speak English both inside and outside the classroom.
My friend suggested that I should go to the theater for a rest.
Many parents urged that educational TV programs be produced with children in mind.
很多家长强烈建议，电视教育节目应该为孩子着想。
这类动词的名词的定语从句或同位语从句也要相应地用虚拟语气做谓语。
The doctor’s suggestion that he be operated on has finally been accepted.
Everyone supports his insistence that smoking be prohibited in school.
3) It is time (that)…句型中。从句的谓语动词用动词过去时表示虚拟，意思是“早该干……”.
It is time we went to school.
It is high time that we made up the missed class.
我们早该把拉下的课补上。
4) would rather / had better / would sooner等词或短语后面的从句中，谓语用虚拟语气，用动词一般过去时。
I’d rather that you left tomorrow.
I would much rather it was forgotten.
我宁愿这事被忘了。
5) 虚拟语气用于 as if / as though 引导的状语从句中，表示和现在、过去或将来的事实不相符。
He talked about the moon as if he had been there.
She stood up as if by doing so she could have corrected everything.
She treats the old man kindly as though he were her father.
6) 用于特殊连词for fear that, lest, in case引导的从句，其虚拟语气形式是should + 动词原形，should常省略。
We dare not play jokes on Miss Liu lest she get angry.
He works hard for fear of failing the exam.
She speaks in a low voice in case she wakens the baby.
7) 用于介词短语表示的虚拟。此类介词有 but for, otherwise, without, with, under more favorable condition, in case of …等。
He worked hard; otherwise he might have failed.
But for his help, I should not have succeeded.
Without you, things would be better.