1.虚拟语气中只有were ,没有was
第三人称单数也用were
在假设的前提条件下,不论哪种时态都用were
2.一般用would should might could 也就够了
区别见下面
would表示将会怎么样或将要怎么样.比用will更委婉、客气.
例：1.Would you like another cake?
2.I would like to go there by car.
should表示应该怎样或将应该怎样.比用shall更委婉、客气.
例：
1.You should go to school by yourself when you're bigger.
2.We should go there now.
must表示应该怎样、必须怎样,就是本身的行为的进行不要考虑客观因素.
例：1.You must listen to the teacher what he says.
2.We must go there wheather it's rainning.
might表示也许可能,一种猜测或未定性的活动.
例：
1.He might have been there.
2.We might get there laterly.
3.were to do和should do都可用在表示对将来情况的虚拟,没有太大区别.should do 还可以用在其他的虚拟语气句式里,比如说suggest +that从句,insist+that从句,等等.
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