同学你好，该知识点来自沪江网校《新概念英语2、3、4册连读【9月班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
这是一个使用习惯。当虚拟条件句的谓语部分含有were, should, had时，我们可以将连词if省略掉，而将were, should, had置于句首。如：

If she were in charge, she would do things differently.
=Were she in charge, she would do things differently.
如果是她负责，她会是另一种做法。

If you should change your mind, no one would blame you.
=Should you change your mind, no one would blame you.
万一你改变主意，谁也不会怨你。

If the management had acted sooner, the strike wouldn’t have happened.
= Had the management acted sooner, the strike wouldn’t have happened.
如果资方早些采取行动，就不会发生罢工了。

祝同学学习进步~