be off (电子产品)停止工作了ex. The computer is off. 电脑停止工作了。go off 当用在闹钟上时表示响ex. The alarm went off. 闹钟响了。set off 开始旅途ex. We set off at 11. 我们11点钟出发。come off 脱落,去掉ex. The label came off. 标签撕掉了。