Thesamething,,wouldhavebeendisastrous.为什麼答案是(A)呢(A)hadithappenedincrowdedplaces(B)ifhappenedincrowdedplaces(C)ifhadhappenedincrowdedplaces(D)ifhashappenedincrowdedplaces

Question

The same thing,_______,would have been disastrous.为什麼答案是(A)呢
(A) had it happened in crowded places
(B) if happened in crowded places
(C) if had happened in crowded places
(D) if has happened in crowded places

Answer 1

虚拟语气,根据虚拟语气的结构 ：
对过去事实相反的假设,
条件从句：过去完成时
主句：should（would）等+have +过去分词 ,根据句子后半部分使用的句型,判断出得使用过去完成时,排除BD
if 引导的条件句中,C缺少主语.
A是虚拟语气倒装句.
虚拟条件句的从句部分含有were,should,或had时,可省略if,再把were,should或had 移到从句的句首,实行倒装.例如：
Were they here now,they could help us.=If they were here now,they could help us.他们现在在的话,就会帮助我们了.
Had you come earlier,you would have met him.=If you had come earlier,you would have met him.你来得早一点,就碰到他了.