Can you see the boys football on the playground? They are my classmates. A. to playB. play

问题补充：

Can you see the boys football on the playground? They are my classmates.

A. to play

B. playing

C. plays

D. played

答案：

A. to play

(答案→)B. playing

C. plays

D. played

解析：see的用过有两个：see sb. do sth.“看到某人做过某事”；see sb. doing sth.“看到某人正在做某事”。本句的意思是“你看到一些男孩在踢足球吗？他们是我的同学”根据题干，说明孩子们正在踢足球，故用playing。所以本题选B。