When basketball you should be careful not to hurt yourself.A. playB. playingC. to playD.

问题补充：

When basketball, you should be careful not to hurt yourself.

A. play

B. playing

C. to play

D. played

答案：

A. play

(答案→)B. playing

C. to play

D. played

解析：可联系答.案.网客服索取。