问题
选择题
that you didn’t care about this matter at all, I should not have wasted my time explaining it to you.
A．Should I realize
B．Had I realized
C．If I realized
D．Did I realized
答案
答案：B
考查条件中与过去事实相反的虚拟语气。其结构为if +主语+had done，主语+would /could/should/might + have done,省略if要倒装，had提前。故选B。