A vast area north of the Yangtze River by the first heavy SNOW of the new year causing dif

问题补充：

A vast area north of the Yangtze River by the first heavy SNOW of the new year，causing difficulties to the post-festival road transport.

A. were affected

B. was affected

C. had affected

D. has affected

答案：

A. were affected

(答案→)B. was affected

C. had affected

D. has affected

解析：

这题考查时态语态，句意是：长江以北的大面积地区被新年的第一场大雪影响，所以用被动式，另外因为主语是单数，所以用was affected，选B。