问题补充：
Our school forbid , that is to say, we are not allowed at school.
A. to smoke; to smoke
B. smoking; smoking
C. smoking; to smoke
D. to smoke; smoking
答案：
A. to smoke; to smoke
B. smoking; smoking
(答案→)C. smoking; to smoke
D. to smoke; smoking
解析：动词搭配forbid doing sth禁止做某事；forbid sb to do sth禁止某人做某事；allow doing sth允许做某事；allow doing sth允许某人做某事；句义：我们学校禁止抽烟，也就是说，在学校里我们不被允许抽烟。第二空使用了allow sb to do sth的被动语态的结构。故C正确。
