_I had time,I would have checked my answers again.A. If B.Unless C.Had D.When

答案是 C

全句分析: 虚拟语气. Had I had time = If I had haven time
如果选A 主句的would要去掉才对
选BC 同样如此.但翻译比较别扭!

C 虚拟语气

语法上：虚拟语气
答案：A

A.

C 虚拟语气
这是一个省略了IF 的条件句,助动词提前. 这里是对过去事实的虚拟,所以用 过去完成时

C.虚拟语气特殊用法。
正常用法是：
与过去相反的虚拟语气。
if i had had time,
特殊用法中， if 省略，had提前，成为Had i had time