Jack is often seen basketball with his friends after school.A. playB. to playC. to playin

问题补充：

Jack is often seen basketball with his friends after school.

A. play

B. to play

C. to playing

D. played

答案：

A. play

(答案→)B. to play

C. to playing

D. played

解析：本题的含义是经常看见Jack和朋友们在一起打篮球，是被动句，看到某人做某事，

在英文中可以说see sb doing或see sb do，在被动句中，后者do变成to do，

故本题只能选B。