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【双11专享班】》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~
当虚拟条件句的谓语部分含有were, should, had时，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。


Had he not been so busy taking the diamonds 相当于If he had not been so busy taking the diamonds

would have done 用于指本该发生而实际上未发生的情况
I would have written before but I have been ill.
本来我是会写信的，但是我生病了所以没写。

blow （用手、武器等的）猛击
She received a severe blow on the head.
她头上挨了重重的一击。


Had he not been so busy taking the diamonds, he would have felt the blow. 如果他不是那么忙着抢钻石，他就会感受到重击。

祝同学学习进步~