One third of the houses destroyed when a terrible earthquake struck the city last night.

问题补充：

One third of the houses destroyed when a terrible earthquake struck the city last night.

A. was

B. were

C. has

D. have been

答案：

A. was

(答案→)B. were

C. has

D. have been

解析：考查时态与主谓一致。当做主语的名词前有分数修饰时，谓语动词与的数该名词保持一直，houses是复数形式，故谓语动词用复数。结合下文当昨晚大地震袭击这座城市时，可知前文叙述的是过去的动作，故用are的过去形式were，选B。