Question

谁能帮我详细地说一下虚拟语气的各种用法

语法书复杂难懂，在下着实心急，请求给予各大师的指点，谢谢~~~
备注：现在我所罗列的两条如下：
1表示与现实或将来事实相反的情况：
主句 从句
WOULD DO 过去式
2表示与过去事实相反的情况：
主句 从句
WOULD HAVE DONE HAD DONE
什么时候用SHOULD？COULD？WOULD？

Answer 1

虚拟语气表示一种不能实现的假设。

判断这个假设是与哪个事实相反。通常有三种情况：
①与过去事实相反。
②与现在事实相反。
③与将来事实可能相反。

三、“后退一步法”

①与过去事实相反，在从句中用过去完成时形式表示。
②与现在事实相反，在从句中用过去一般时形式表示。
③与将来事实可能相反，在从句中用过去将来时形式表示。

主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。

例：If I had come her yesterday, I would have seen him.
If I were a teacher, I would be strict with my students.
If it should snow tomorrow, they couldn’t go out.

Answer 2

还要注意另外几种句型:
1. would rather sb did sth .
would rathe r sb had done sth .
2. It is time that sb did sth .
3. ...wish that sb were to do sth .
...wish that sb did sth .
4. ...suggest/advise/demand /insist/request/order that sb (should) do sth .
5. it is important/necessary/ natural tha sb (should) do sth

Answer 3

考试虫大学英语语法满好的,我们学校都在用