He his aunt’s when he went to Wuhan on business. A. called on B. called at C. dropped in

网友回答

A. called on
(答案→)B. called at
C. dropped in on
D. dropped in
解析：词义用法辨析。call on 号召，call at 拜访  drop in on sb拜访drop in 拜访（不及物） 句意为“当他去武汉出差时他顺便拜访了姑姑家。”  his aunt’s为处所而C项要搭配人作宾语所以答案为B。