stop sb. (from) doing sth =prevent sb. (from) doing sth. =keep sb. from doing sth. 阻止某人做某事 The teacher stopped us (from) talking during the exam. 老师阻止我们在考试期间说话。 The new rule prevented students (from) using phones in class. 新规定阻止了学生在课堂上使用手机。 The strict rules kept the students from cheating on tests. 严格的规则阻止了学生在考试中作弊。 keep sb. from doing sth.中的from不可以省略，因为keep sb. doing sth. 是“让某人持续做某事”的意思，意思完全不同。 It was very thoughtless of you to keep her waiting so long. 你让她等那么久也太不体谅人了。