Thehazeorsmogwassoseriousthatthewinterrunning

問題詳情：

 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

知識點：虛擬語氣與情態動詞

題型：選擇題