(3rd sing. present and past ought)with infinitive
1
- used to indicate duty or correctness, typically when criticizing someone's actions常用于批评某人行为, 表示责任、义务、正确性 应当, 应该：
they ought to respect the law
他们应该尊重法律
it ought not to be allowed.
它不该得到允许。
1.1
- used to indicate a desirable or expected state表示愿望或期望 该, 应该：
he ought to be able to take the initiative.
他应该能采取主动。
1.2
- used to give or ask advice表示给予忠告或请求别人的忠告 该, 应该：
what ought I to do?
我该做什么？
2
- used to indicate something that is probable［表示可能］ 该, 应该：
five minutes ought to be enough time.
五分钟该足够了。
USAGE
The verb ought is a modal verb and this means that， grammatically， it does not behave like ordinary verbs. In particular， the negative is formed with the word not alone and not also with auxiliary verbs such as do or have. Thus the standard construction for the negative is he ought not to have gone. The alternative forms he didn't ought to have gone and he hadn't ought to have gone， formed as if ought were an ordinary verb rather than a modal verb， are found in dialect from the 19th century but are not acceptable in standard modern English.
词源
Old English āhte, past tense of āgan 'owe' （see OWE）.