Students are ________．
A.prevented to smokeB.forbidden to smokeC.stopped to smokeD.preventing from smoking在线课程B
解析：
句意：禁止学生吸烟。prevent, stop的句式：sb．is/are prevented/stopped from doing，在这儿的形式不对；
sb．is/are forbidden to do某人被禁止做某事。