I didn't send out my application from last week, but I ( ).

I didn't send out my application from last week, but I ( ).
A、had to
B、might have to
C、have had
D、should have
【正确答案】：D
【题目解析】：should have 表示虚拟，本该要做，实际未做。句子含义是上周，我没有寄出我的申请表，其实我本该这么做的。