He kept his head otherwise the accident would have happen

问题描述:

He kept his head otherwise the accident would have happen
为什么用would have happen 而不用过去时happened或用would happen呢
不好意思 happen 应改为happened

是would have happened.情态动词过去时 + 完成时表示对过去事情的推测.这里也是一样..表示推测"要不是他kept his head,就会发生一场事故"...例如:I would have done my homework if I wasn't ill.如果不是我病了,我...