问题补充：
We shouldstudents computer games.
A. keep; from play
B. stop; from play
C. stop; from playing
D. keep; play
答案：
A. keep; from play
B. stop; from play
(答案→)C. stop; from playing
D. keep; play
解析：句意：我们应该阻止学生玩电子游戏。stop sb from doing sth意为“阻止某人做某事”，其它形式表达都不对；故选C。
