1．表示出于义务、责任、道义等方面的要求而该做某事。
◆To hand in the paper in time, we ought to have a busy schedule. 为了及时交上论文，我们的日程应该紧一点。
◆To build up our body, we ought to do enough exercise, such as running, swimming and hiking.
为了增强体质，我们应该做足够的运动，比如跑步、游泳和远足。
2．表示说话人的猜测。
◆She ought to succeed, because she tries hard enough.
她应该能成功，因为她确实够努力。
◆The two teams are equal in ability, so the game between them ought to be a close one. 这两队能力相当，因此他们之间的比赛应该是一场势均力敌的比赛。
3．ought to的否定式是在ought后加not，疑问式是将ought提前。
◆If you make a promise, you should keep it and you ought not to break a promise.
如果你做出了承诺，你就应该遵守诺言，不应该食言。
◆—Ought I to write to say thank you?
——我应该写封感谢信吗？
—Yes, I think you ought (to)．
——对，我认为你应该写。
