题一：
Maybe if I _______ science, and not literature then, I would be able to give you more help.
A. studied B. would study C. had studied D. was studying
题二：
I ______ sooner but I didn’t know that they were waiting for me.
A. had come B. was coming C. would come D. would have come
题三：
We ___ __ John’s name on the race list yesterday but for his recent injury.
A. will put B. will have put C. would put D. would have put
题四：
—Pity you missed the lecture on nuclear pollution.
—I____ it, but I was busy preparing for a job interview.
A. attended B. had attended C. would attend D. would have attended
