问题补充：
Had it not been for the haze（霾）weather phenomenon, there fewer car accidents in Beijing then．
A. would have been
B. were
C. may be
D. would be
答案：
(答案→)A. would have been
B. were
C. may be
D. would be
解析：考查虚拟语气：句意：要不是因为雾霾天气，那时北京的交通事故会更少，从Had it not been for the haze（霾）weather phenomenon,可知是和过去相反的虚拟条件句，相当于：If it had not been for the haze（霾）weather phenomenon,所以主句也是和过去相反的虚拟语气，用would have done，选A。
