present and future unreal conditionals和past unreal condition

第一个是现在和将来虚拟条件句.第二个是过去虚拟条件句.
第一个是对现在或将来的情况进行假设；第二个是对过去的情况进行假设.
例如:
if i had enough money,i would buy a big house.如果我有钱,我就买所大房子.对现在情况的虚拟.从句用一般过去时,主句用would/should/could/might+ do
if i were free tomorrow,i would help you.如果我明天有空,对将来的虚拟.从句用一般过去时,主句用would/should/could/might+do
if you had took part in the meeting yesterday,you would have known what we talked about.如果你去看了这部电影昨天参加了会议,你就会知道我们讨论了什么.对过去情况的虚拟.从句用过去完成时,主句用would/should/could/might+have done
还有一些其他形式,查看虚拟语气就可以了