问题补充:
for the free tickets, I would not have gone to the films so often.
A. If it is not
B. Were it not
C. Had it not been
D. If they were not
答案:
A. If it is not
B. Were it not
(答案→)C. Had it not been
D. If they were not
解析:句意:要不是免费的票,我不会这么经常去看电影。从主句中would not have gone可以看出是与过去相反,故从句应该使用had done. C答案省略了if,提前had,相当于if it had not been. 故选择C。