They used basketball in the park.A. playB. to playC. playingD. to playing

问题补充：

They used basketball in the park.

A. play

B. to play

C. playing

D. to playing

答案：

A. play

(答案→)B. to play

C. playing

D. to playing

解析：本题的含义是他们曾今习惯在公园里打篮球，used to+动词原形，表示曾今习惯做某事，故本题选B。