必修三英语unit1情态动词的用法

“可能” “不可能”
否定、疑 问句中
补充：金版12页右边第4点
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May I eat KFC if I finish my
homework?
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may/might:
1. 表示许可。表示请求、允许时， might比may的语气更委婉一些。 — Might/May I use your computer? — Yes, you can. /No, you can’t/you may not / you mustn’t.
Modal Verb
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情态动词
情态动词表示说话人的语气和情 态的动词。
语气：能力、义务、建议、允诺、 许可、推测。
情态：情感和态度。
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观察下列各句，注意谓语动词形式。 1.He can finish the paper in an hour.
2.Would you please pass me the dictionary?
11.. cI caann/表am示a现bl在e t的o s能wi力m. 22.. cI coouulldd表/ w示as过ab去le的to能cli力mb a tree when I
was a child.
3. be able to 表能力，可用于多种时态
3. I will be able to swim next week.
(除ought to “应该”和have to“不得不”外) 2.情态动词没有人称，数的变化。 3.有些情态动词有一般式和过去式，过去式比一
般式更委婉。 如can-could , will-would, may-might, shall-should
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建议, 请求, 允许, 能力
1. Jim isn't good at maths, but he can speak
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3. 表“可能性”，译为“可能”； Can this news be true? Where can they be? 否定句中，翻译为“不可能” She can’t have left school, for her
bike is still here.
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情态动词 含义
否定式
注意点
表能力 caห้องสมุดไป่ตู้’t
can, may, will. 3 can 用于肯定句中, 可表示”有时可能”
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情态动词 含义 否定式
注意点
表能力 can’t/couldn’t 区别 be “能，会”“不会，不能” able to
can / could
表许可 can’t /couldn’t
“可以” “不可以，不许”
表推测 can’t /couldn’t 主要用于
4. be able to 强调某人通过努力克服 4困. 难Th成e f功ire地sp做re了ad某th事rough the hotel very
quickly but everyone was able to get out
2. 表“许可”，译为“可以”， could比can语气较委婉。用can 或 cannot / can’t 回答 --Can /Could I borrow your bike for a moment? --Yes, you can. / No, you can’t.
English well. 能力
请求/
2. May I have a look at your Iphone? 允许
3. Would you like to join my family for dinner? 请求
4. When going by plane, you should arrive on
During the vacation he would often visit me.(过去式)
4. 某种特定情况下真实或可能的事情 At that time, people would starve if
3.She may be very busy now.
4.I will never forget the days we spent together.
5.We should help each other.
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情态动词的语法特征
1.不能单独做谓语，即是情态动词+动词原形。
例如：I can swim.（谓语）
区别 be able
“能，会”“不会，不能” to
can / could
表许可 “可以” 表推测 “可能”
can’t
代替may
“不可以，不许”
can’t “不可能”
主要用于否定、 疑问句中
1表示某人通过努力克服困难做成某事,要用was / were able to. 2 could, might, would 表委婉语气用于疑问句, 答语仍须用
2. We will help him if he asks us to. 表“意志，意愿”，译为“会” 过去时：would
I promised that I would do my best.
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3. He will always take a walk after supper. 习惯上会发生的事情
time.
建议
5. When you eat fish, you must be very careful with the bones. 建议
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情态动词语法目录 一、can / could 二、may /might 三、will /would 四、shall / should 五、must
一、情态动词表能力
表许可 mustn’t 不许，严禁 “可以”may not 最好不要 表推测 may not
“可能”可能不
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will 和 would
1. Will you give him a message when you see him. 用于第二人称，表“询问意愿，提出 请求” would you(用于现在时)语气更为婉转
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may/might:
2.用于祈使句中表示祝愿。 May you be happy all your life.
Ma祝y你y成ou功s！ucceed. 3.表示推测、可能（只用于肯定句， 疑问句则要用can或could）。
He may be very busy now.
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情态动词 含义
否定式
may / might