The paintings are on show in the history museum.A. on timeB. on watchC. on dutyD. on displ

问题补充：

The paintings are on show in the history museum.

A. on time

B. on watch

C. on duty

D. on display

答案：

A. on time

B. on watch

C. on duty

(答案→)D. on display

解析：on time 按时,准时;on watch 值班,监视;on duty值班,上班;on display展览,公开展出.句意:这些绘画正在历史博物馆展出.结合语境可知选D.