情态动词

情态动词辨析（can/may/must等等）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用来回答
      • Could use your dictionary? yes,you, can .
    • could语气委婉
  • 能力（Ability）
    • can表，现在，将来
      • She can swim. but she couldn'tlast year.
    • could表过去
  • 可能性Possibility，常用于否定句中
  • can VSbe able to
    • "能力互换"
    • 过去时，could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/may not.
  • 可能
    • 不用于否定，疑问，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…的样子
• will/would
  • 疑问句，请求建议，would和won′t语气更委婉无时态.
  • 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性动作或某种倾向” 过去时，would=used to
    • Boys will be boys. Tom will taik for hours if you give him a chance.
• shall
  • 用于，第一三人称 疑问句中，“征求对方意见或对方请示”
    • 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.whether you want it or not.
    • you shall pay for it.
• should
  • 劝雪建议，“应该” 道义上的责任义务，ought to
    • We should/ought to learn about the computer and make full use of it.
    • You are hus father.you ought to take care of him
  • 推测，可能，“按道理应该”
    • 一般结论后面加证据，推测
  • 说话人的感情
    • Why should I go?
    • She should be so stubbom.她竟然
• must
  • 必须Necessary.语气更强烈 否定提问用needn′t或doesn′t have to mustn't表禁止，劝雪，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
    • 推测强度 Must will would ought to should can couldn't may might
• need
  • 疑问句，肯定回答must 否定needn't
  • need doing被动 实意助词
• dare
  • 否定疑问条件句中居多
  • 实义助词，肯定句dare to 否定疑问句，dare
    • l dare to jump down from the top
    • She doesn't dare face her teacher.
• 情态动词+have done
  • must have done过去一点做过 can′t/couldn′t have done过去一点没做过
    • I must have seen you somewhere. The room can't have been cleaned.
  • may/might have done没那么肯定
  • could have done不能够做但没做成，哎
  • should have done/ought to have done本应该，却没有 should not have done/ought not to have done,本不应该干啥非得干
    • They ought to have complete and their work much earlier.
    • You shouldn′t have your son along at home.
  • needn′t have done本来不用于非得没事找事
• can
  • 只有过去时和现在时
  • 一般指自身具有的能力
• be able to
  • 有更多的时态变化
  • 经过一致努力后具有的能力=manage to go