情态与语气

英语语法之情态动词和动词语气，包括：称述语气、祈使语气、虚拟语气、疑问语气、条件语气、感叹语气、情态动词等内容。

动词语气

• 称述语气
  • 描述现实 The rabbit ate the carrrot.
• 祈使语气
  • 命令/请求 Rabbit,eat the carrot. 绝大数情况下： 使用第二人称(“你”)并使用一般现在时态； 去掉“你”，并保证V原 You eat the carrot!>>>Eat the carrot! You don't eat it!>>>Don't eat it! You are quiet!>>>>Be quiet!
• 虚拟语气
  • 表示“不可能”假设
    • 与现在事实相反或主观意愿
      • 条件句：过去式 主句：would + V原 If I knew it, I would tell you. 如果我现在知道(但实际我不知道),我现在会告诉你。
    • 与将来可能性较小的事实相反
      • 条件语句中的虚拟语气词：should + V原 主句中使用：would V原 If should meet thee after long years,how should I greet thee? 万一将来我们重逢了，我又该如何面对你？
    • 与过去事实相反
      • 条件句：had + V过去分词 主句：would have + V过去分词 If I had watched this video before,I would have aced my test.
  • 表示愿望，请求，建议，命令等
    • 希望某个动作/事件发生
    • 对现在的愿望
      • wish + V过去式 I wish that I were a rabbit.
    • 对过去的愿望
      • wish had/would have + V过去式 I wish (that) I had eaten carrot.
    • 对将来的愿望
      • wish should + V过去式 I wish should (that) I could the carrot.
• 疑问语气
• 条件语气
• 感叹语气
• 情态动词
  • 概述
    • 给谓语动词添加感情色彩，表示说话人对有关行为或事物的态度和看法。
  • 用法
    • 不能单独作谓语，必须接动词原形。 情态动词+V原
  • 表“推测”
    • 绝大多数情态动词可以表“推测“，但其程度有所差异。 must > will > would > ought to > should > can > could > may > might must have done”表肯定的推测” The road is wet.It must have rained yesterday. can’t have done “表对过去的否定推测” He can’t have said such a foolish thing. could/may/might have done ”或许已经做过了某事” Mr.Lin didn’t come to work,so he might have been ill.
    • 对现在或将来的推测，情态动词+动词原形
    • 对过去的推测，情态动词+have done
  • 基本含义及其用法
    • 1. can & could & be able to “能”
      • 表示能力
      • 表示许可;表“许可“时can与may可互换
      • 表示语气婉转，使用could
      • can 和 be able to 表示能力
        • can:强调自身的能力，只有现在式和过去式 be able to :强调通过努力而获得的能力，有多种事态(be) Can you see it these? He is/was/will be able to help you.
    • 2. may & might “可以”
      • 表示允许或征询对方许可 You may use my dictionary.
    • 3. must & have to “必须
      • must :无时态变化； 否定：needn’t
        • mustn’t:”不准，不许可或禁止”
      • have to :有时态变化
    • 4. should do& ought to do ”应该”,但out to 语气更强一些。
    • 5. shall & will “将”
    • 6. need “需要”
      •  情态动词 He needn’t worry about us now.  实义动词 You need to practice reading aloud everday.  主语为物时，可用主动表被动 My bike needs repairing.==My bike needs to be repaired.
    • 7. had better ”最好”
      • 肯定：had better do sth
      • 否定：had better no do sth
    • 8. would & used to “过去常常做某事“
      • 表示”过去反复发生的动作“
        • I used to play cards a lot,but now I seldom play.
      • 委婉地提出建议、请示
        • Would you like sth?或Would you like to do sth? Would you like to do moring exercise? Would like to do sth.”需要，愿意做某事” I would like to take a taxi.
  • 使用于虚拟语气中
    • could
      • could have done “能做的事，却没有做”
      • couldn’t have done “无能力做的事，但做到了”
    • need
      • needn’t have done “过去不需要做，但做了”
    • should
      • should/ought to have done “该做的，没有做”
      • shouldn’t/oughtn’t to have done “不该做的，却做了”
    • might
      • might have done “有可能做的事，却没有做”
      • might have done “本不可能做的事，但做了”