情态动词

情态动词的思维导图，介绍了can&could、may&might、attention、should、shall等知识，一起来看。

情态动词

• can&could
  • could是can的过去式，或表委婉
  • can、could：表能力be able to：表结果
  • 表允许
    • you can go now
  • 表可能（依据逻辑或习惯可能发生，常于频度副词连用）
    • He has a good memory ,but he can be forgetful at times.
  • “有时会”
    • It can be rather cold in winter.
  • 表惊讶
    • How can you do this to me?(怎么能）
  • 表轻微责备（仅could）
    • You could write more clearly.
• may&might
  • might是may的过去式，或表委婉
  • 表允许
    • you may kiss your wife now.
  • 表可能（依据事实有可能发生）
    • He may be forgetful becuase of his injury in the head.
  • 表祝愿
    • May you success.
  • 表轻微责备（仅might)
    • You might work harder.
  • “很可能”
    • may/might as well不妨
• attention
  • 对过去的猜测
    • 肯定must have done
    • 否定can't have done
    • 可能may/might have done
  • must的否定形式为can't
  • must 后接动词进行时态，可表示不耐烦语气
• should
  • 表应该（义务、责任）
  • 表推测
    • It should be Tom,although the evidence is not enough to make sure.
  • 表竟然
    • I'm surprised that she should have done such a thing.
  • 虚拟
  • • 应做未做should have done
    • 本不应做但做了shouldn't have done
    • 能做未做could have done
• shall
  • 向第一、第三人称征求意见
  • 第二、三人称陈述句表命令、警告、允诺
  • 法律规定的义务
    • convention规定
• 易混
  • can not/never…to/enough…无论……也不过分
  • 只得做
    • can't but
    • can't choose but
    • can't help but do sth
  • can't help to do 不能帮忙做
  • can't help doing 情不自禁做
  • may well 很可能