When Mr Wang was young he in the river.A. uses to swimB. used to swimC. used to swimming

问题补充：

When Mr Wang was young, he in the river.

A. uses to swim

B. used to swim

C. used to swimming

D. used swim

答案：

A. uses to swim

(答案→)B. used to swim

C. used to swimming

D. used swim

解析：句意：当王先生年轻的时候，他经常在河里游泳。“过去常常做某事”是used to do。故选B。