ought to

modal verb

/ˈɔːt tə/, before vowels and finally /ˈɔːt tu/

动词形式

ought not to
(especially British English)oughtn't to	/ˈɔːtnt tə/, before vowels and finally /ˈɔːtnt tu/ /ˈɔːtnt tə/, before vowels and finally /ˈɔːtnt tu/

used to say what is the right thing to do应该；应当
- They ought to apologize.他们应该道歉。
- They ought to have apologized (= but they didn't).他们本该道歉的。
- Such things ought not to be allowed.这种事应该禁止。
- He oughtn't to have been driving so fast.他本不该把车开得那么快。
- (formal) ‘Ought I to write to say thank you?’ ‘Yes, I think you ought (to).’“我应该写信致谢吗？” “对，我觉得你应该。”
Questions beginning with ought are rare; it is more usual to begin with Do you think: Do you think I ought to write and say thank you?
Grammar Point should / ought / had better
should / ought / had better
- Should and ought to are both used to say that something is the best thing or the right thing to do, but should is much more common:should 和 ought to 均用以表示应该做某事，不过 should 常用得多：
  You should take the baby to the doctor’s.你应该把这婴儿带去看看医生。
  I ought to give up smoking.我应该戒烟。
  In questions, should is usually used instead of ought to:在疑问句中，通常用 should 而不是 ought to：
  Should we call the doctor?我们叫医生来好吗？
- Had better can also be used to say what is the best thing to do in a situation that is happening now:had better 亦可用以表示在目前状况下最好做某事：
  We’d better hurry or we’ll miss the train.我们最好快点，否则就赶不上火车了。
- You form the past by using should have or ought to have:过去时用 should have 或 ought to have 构成：
  She should have asked for some help.她本应该请求帮助的。
  You ought to have been more careful.你本应该更小心一点的。
- The forms should not or shouldn’t (and ought not to or oughtn’t to, which are rare in North American English and formal in British English) are used to say that something is a bad idea or the wrong thing to do:should not 或 shouldn't（以及在美式英语中很少见，在英式英语中为正式用法的 ought not to 或 oughtn't to）表示不应该：
  You shouldn’t drive so fast.你不应该把车开得这么快。
- The forms should not have or shouldn’t have and, much less frequently, ought not to have or oughtn’t to have are used to talk about the past:should not have 或 shouldn't have 以及很少用的 ought not to have 或 oughtn't to have 均用于指过去：
  I’m sorry, I shouldn’t have lost my temper.对不起，我不该发脾气。
used to say what you expect or would like to happen（表示期望或可能发生的事）应该
- Children ought to be able to read by the age of 7.儿童 7 岁时应该识字了。
- Nurses ought to earn more.护士的薪资应该多一点。
used to say what you advise or recommend（表示劝告或建议）应该
- We ought to be leaving now.我们现在该动身了。
- This is delicious. You ought to try some.这个菜很可口，你可得尝尝。
- You ought to have come to the meeting. It was interesting.会议可有意思了，你真该参加。
Topics Suggestions and adviceb1
used to say what has probably happened or is probably true（表示可能发生的或真实的事情）应该
- If he started out at nine, he ought to be here by now.他如果九点出发，现在应该到这里了。
- That ought to be enough food for the four of us.这些食物应该够咱们四个人吃了。
- Oughtn't the water to have boiled by now?水现在该开了吧？
Topics Doubt, guessing and certaintyb2

Grammar Point modal verbsmodal verbs

The modal verbs are can, could, may, might, must, ought to, shall, should, will and would. Dare, need, have to and used to also share some of the features of modal verbs.can、could、may、might、must、ought to、shall、should、will 和 would 均为情态动词。dare、need、have to 和 used to 亦具有情态动词的某些特性。
Modal verbs have only one form. They have no -ing or -ed forms and do not add -s to the 3rd person singular form:情态动词只有一种形式，没有 -ing 或 -ed 形式，第三人称单数也不加 -s：
- He can speak three languages.他会说三种语言。
- She will try and visit tomorrow.她明天将设法去参观。
Modal verbs are followed by the infinitive of another verb without to. The exceptions are ought to, have to and used to:情态动词后跟不带 to 的动词不定式，但 ought to、have to 和 used to 例外：
- You must find a job.你必须找到一份工作。
- You ought to stop smoking.你应当戒烟。
- I used to smoke but I gave up two years ago.我过去抽烟，但两年前就戒了。
Questions are formed without do/does in the present, or did in the past:疑问句现在时不用 do/does，过去时不用 did：
- Can I invite Mary?我可以邀请玛丽吗？
- Should I have invited Mary?我本该邀请玛丽吗？
Negative sentences are formed with not or the short form -n’t and do not use do/does or did.否定句用 not 或简约式 -n't，不用 do/does 或 did。

You will find more help with how to use modal verbs at the dictionary entries for each verb.情态动词的不同用法可参考本词典里各情态动词词条。