ought to modal v (neg 否定式 ought not to; contracted form 縮約式 oughtn't to ) 1 (a) (indicating obligation 表示責任或義務) We ought to start at once. 我們應當馬上動身. You ought to say you're sorry. 你應該說聲對不起. Such things ought not to be allowed. 這類事不該容許. They oughtn't to let their dog run on the road. 他們不該把狗放出來滿街跑. `Ought I to write to say thank you?' `Yes, I think you ought (to).' ｀我應該寫封感謝信嗎?＇｀對, 我看應該寫.＇ She ought to have been more careful. 她本該小心些. =>Usage 1 at must 見must所附用法第1項. (b) (indicating advice or recommendation 表示勸告或推薦) You ought to improve your English before going to work in America. 你應該把英語學好些再去美國工作. There ought to be more buses during the rush hour. 高峰期間應該多開幾趟公共汽車. You ought to see her new film. 你應當看看她新拍的電影. She ought to have been a teacher, ie She would probably have been a good one. 她本該當教師（很可能是個好教師）. =>Usage 2 at must 見must所附用法第2項. 2 (drawing a tentative conclusion 作推測性的結論) If he started at nine, he ought to be here by now. 要是他九點出發, 現在該到這兒了. That ought to be enough food for all of us. 那些該夠我們大家吃的了. Look at the sky it ought to be a fine afternoon. 看看天--下午一定很晴朗. =>Usage 3 at must 見must所附用法第3項.