问题
The joke was so interesting that we all burst out laughing. Never before __________ heard a joke like that.
A:I have
B:I had
C:have I
D:had I;
B:I had
C:have I
D:had I;
正确答案是：
同类题型
It was no surprise that an awful accident ____ occur the day when they were drunk
, once _______ positive for H7N9 flu virus, willreceive free medical treatment from our government.
_____ he comes, we won’t be able to go
He paid for a seat, when he _____ have entered free.[ ]
It __be the vocabulary that caused you the problem in the exercise because you know a lot of words.