Thehazeorsmogwassoseriousthatthewinterrunning
问题详情:
The haze or smog was so serious that the winter running _________. Some students complained as they ran.
A. could have cancelled B. should have cancelled
C. must have been cancelled D. ought to have been cancelled
【回答】
D
知识点:虚拟语气与情态动词
题型:选择题