情态动词

情态动词相关语法知识总结的思维导图分享！下图详细地讲解了情态动词的定义、位置、用法、功能以及情态动词的句法特征等多个方面的知识要点，值得收藏学习。

情态动词

• can/could
  • 请求和允许(Permission)
    • can来回答
      • —Could use you dictionary？—Yes ，you can.
    • counld语气委婉
  • 能力(Ability)
    • can表 现在，将来
      • She can swim ，but she counldn's year。
    • counld 表过去
  • 可能性Possibility .常用于否定句中
  • can VS be able to
    • 能力互换
    • 过去时，counld一般能力，was/were able to do=manage to do.
  • can't…too… 再…也不为过
    • You can’t be too careful when crossing the street.
• may/might
  • 允许
    • May i ask where you were born? Yes,you may/No,you mustn’t/mayn’t
  • 可能
    • 不用于疑问，否定 might只有语气无时态
  • 祝愿
    • May you succeed!
  • may/might …as well may/might as well 不妨…，还是…好 You may as well stay here.
• will/wonld
  • 疑问句，请求建议 would和won't更委婉，语气无时态 would you提问，will回答
  • 意愿willingness 意图intention 决心Determination 承诺Promise=be willing to
  • 表示“没有固定时间的习惯动作或某种倾向” 过去时，would=used to
    • Boys will be boys
    • Tom will talk for hours if you give him a chance.
• 情态动词+have done
  • mast have done 过去一定做过
    • I must have seen you somewhere.The room can’t have been cleaned.
  • can't/couldn't have done 没那么肯定
  • could have done 本能够做单没能完成
  • should have done/ought to have done 本应该，却没有 should not have done/ought not to have done.本不该干啥，非要干
    • They ought to have completed their work much earlier.
    • You shouldn’t have left your son alone at home.
  • needn't have done 本来没事干，非得没事找事干
• dare
  • 否定疑问条件句中居多
  • 实义动词，肯定句dare to，否定疑问句，dare
    • I dare to jump down from the top.
    • She doesn’t dare face her teacher.
• need
  • 疑问句，肯定回答must 否定回答needn't
  • 实义动词
    • need doing 表被动
• must
  • 必须Necessity.语气更强烈 否定提问用needn't或doesn't have to. mustn't表禁止，劝告，主张
    • You mustn’t miss the movie.
  • must和have to must必须 have to 不得不
  • 推测Deduction must只用于肯定句，在否定句中用can't/couldn’t 和can/could 形式：must be/do must be doing must have done
    • Must will would ought to should can could may might.
• should
  • 说话人的感情
    • Why should I go?
    • She should be so stubborn.她竟然
  • 推测，可能，“按道理应该”
    • 一般结论后面加证据，推测
  • 劝告建议，“应该”道义上的责任义务，ought to
    • We shouldn’t/ought to learn about the computer and make full use of it.
    • You are his father,you ought to take care of him.
• shall
  • 用于第一，三人称的疑问句中，“征求对方意见或向对方请示”
    • Shall he come tomorrow 你要他明天来吗？
  • 第二，三人称肯定句，命令，警告，强制，允诺
    • You shall do it.whetheryou want it or not.
    • you shall pay for it.