必修3 Unit 1 Festivals around the world Grammar 课件（23张PPT）

(共23张PPT)
Unit 1 Festivals around the world
Grammar：情态动词
高一必修3
概述
①表示说话人对某一动作或状态的语气或情绪；
②不可单独做谓语,必须和动原连用，否定+not；
③无人称、数的变化。
基本用法
can/could
表示能力。
I can speak English.
She can lift her husband up with one hand.
Tips： 如果表示过去某人有能力做某事，而且做成了某事，要用were/was able to = succeeded in.而could一般只表示过去有能力做, 但做了与否未知。
The fire spread through the hotel very quickly but everyone ____ get out.
can B. could
C. was able to D. were able to
C
表示请求(request)
The kid: ‘‘Can/could I watch TV for a while ”
Tips：此时could 不是过去式，而是表示委婉语气。
表示许可(permission) 。
The mother: “You can watch TV for 5 minutes.”
表示惊讶，怀疑或不相信，主要用于否定句, 疑问句, 感叹句。(doubt)
How can you do such a thing
Can the woman be his wife
can 可表示一时或偶尔的可能性。
She had a bad temper(脾气)，but she can be gentle(温柔) sometimes.
It is warm in March in my hometown, but sometimes it can be very cold.
Tips：此时句中一定有表示一时或偶尔的时间状语。
may, might
表示请求(request)
What award did you get from the sports competition
May I have a look
表许可(permission)
You may leave home.
She said you might watch TV .
Tips：在一般疑问中，can/could/may/might都可表示请求，但给予许可只可用can/may。
—Can/could/may/might I watch Happy Camp
—Yes, you can/may.
may 表示现实的可能性(possibility)
Jane may be a millionaire someday.
Our football team didn’t play very well today, but we might do better tomorrow.
may 可表示祝福，祝愿
May you succeed! May God be with you!
May happiness and health always follow you.
句型：May+主语+动原!
May your dream come true.
must
表示：必须，一定
否定：mustn’t
You mustn’t speak ill of others behind his back .
Tips：在回答must的一般疑问时,肯定时,用must；否定时,如想表达‘不必’之意,用needn’t/don’t have to。
—Must I clean the dishes now
—Yes, you must.
/No, you needn’t. /you don’t have to.
语气很强,不准、禁止
表示一个人的固执坚持，偏偏，一定, 非得
Why must you sing at night
Must you go to the film when you are one
用于一，三人称的疑问句中，表示说话者征求对方的意见或请求指示
Shall we go out for lunch？
Shall he come in or wait outside
When shall he leave the hospital
用于二，三人称的陈述句中，表示说话人强烈的感彩，如: 命令，警告，允诺等
Everyone shall wear uniform.
If you don’t work hard, you shall fail in exam.
He shall get half of the company according to the will(遗嘱).
shall
用在条约、规定、法令等文件中表示义务或规定，意为“应该，必须”。
No person shall carry a mobile phone into the examination room during the College Entrance Examination.
should
表示义务、责任（应该,应当）
You should do as the teacher says.
用于一些表示感情的从句中，意为“竟然”
I’m surprised that he should have been cheated by a 3-year-old boy.
will, would
用在第二人称疑问句中，征求意见
Will you drink some milk tea
Would you drink some milk tea
表示更加委婉的语气,更加客气
表示主语的意愿、决心，即：主语自愿做某事 = 愿意
I will come up and help you in a moment.
- Will you lend me a hand
I’d love to. /Yes, I will.
will 可表示现在的经常性的动作或行为，译为 “常常，就会”；
would可表示过去的经常性的动作或行为，译为“过去常常”。
Eg. If nobody is at home, we will have dinner outside.
We would enjoy a cup of coffee after work when we worked in WS.
基本用法
can/could
may/might
shall
should
must
will/would
能力；请求；许可；理论或逻辑上的可能性；
一时或偶尔的可能性（sometimes, at times）
请求；许可；现实的可能性；祝福，祝愿；may/might as
well do…(还是…的好，不妨) ；may well do… (很可能做…)
用于一，三人称的疑问句中，表示说话者征求对方的意见或
请求指示；用于二，三人称的陈述句中，表示说话人强烈的
感彩，如：警告，威胁，允诺，规定等
应该，应当；竟然；
必须，一定是(否定：mustn’t, needn’t/don’t have to, can’t)；
偏偏，非得，一定 ( Why must you sing at night )
第二人称疑问句中，征求意见(would更加委婉)；主语的意
愿、决心，自愿做某事；will 常常、就会；would 过去常常
判断推测
MV + 动原
must 表示判推时，意为：一定、必定， 只用于肯定句
Eg. The light in her room is still on; she must be at home now.
can 表示判推时，只用于否、疑问中(can’t)，是比较肯定的否定，意为：不可能， 可能…吗？
Eg. She can’t be at home. I saw her leave home ten minutes ago. She forgot to turn off the light.
could 表示判推时，意为：可能、也许， 可用于各种句式，此时，could不是表示过去，而是一种不肯定的语气。
Eg. Xiao Shenyang could be from Liaoning Province.
Where could he be from
may, might 表示判推时，均为：可能、也许，
此时,might不表示过去,而表示可能性比may小,更无把握。
Tips： a. 在表示判推时，must的否定式为：can’t/couldn’t, 疑问句时使用can/could
b. 在表示判推时, can’t/couldn’t = 不可能
may not/ might not = 可能不
eg. He must be a student.
He may be a student.
He can’t be a student.
He may not be a student.
c. 在肯中，could/may/might 都可表示可能
should/ ought to 在表示判推时，均意为：应该、应当，是按照常理推断，具有一定的依据，语气比must弱
—When can I come for the photo I need it tomorrow.
—It ____ be ready by 12:00.
A. should B. must C. may D．might
MV + have + done
should/ought to + have done
过去本应做某事，但并没有做
否定：should not/ought not to + have done
Eg. You should/ ought to have been kind to your husband.
你不应该与你老公打架的.
You shouldn’t/ought not to have fought with your husband.
must have done 过去一定做过或完成过某事，只用于肯定句中。
You must have heard of Xiaoshenyang’s English name.
He must have been mad last night.
can’t have done
只用于否定、疑问句中，表示不可能做过某事
must have done 的否定形式
The moon can’t have been full last night.
He can’t have finished his homework today.
could have done 可用于各种句式
在否、疑中: couldn’t have done
= can’t have done
在肯中，有两种含义：
a.过去可能做过或完成某事：
He could have been mad.
b. 本能够做某事，但没做，有时含有委婉批评
He could have married the girl he wanted to.
You could have asked me for help.
may have done 表示过去可能做过或者可能已经完成了某事，只用于肯定句、否定句中：
You may have heard of Xuriyanggang.
You may not have heard of Xuriyanggang.
needn’t have done 表示过去本来没必要做,但做了，译为“本不必要”
didn’t need to do 表示过去没必要做，也没做
We needn’t have learnt so much English grammar.
We didn’t need to learn so much English grammar.
判断推测
Mv+动原(现在or将来) Mv+have done(过去)
must
can
could
may/might
should
ought to
need
一定、必定，只用于肯定句
用于否、疑问中，比较肯定
的否定，can’t意为：不可
能，疑问句中:可能…吗？
可能、也许,可用于各种句
式，could不是表示过去，
而是不肯定的语气。
可能、也许，只用于肯定和
否定句，不用于疑问句，
might不表示过去,而表示可
能性比may小,更无把握。
应该是、理应…,是按照常理
推断，具有一定的依据
must have done肯定做过某事
can’t have done不可能做过某事
(must have done的否定)
couldn’t have done=can’t have
done; could have done过去可能
做过; 本能够做某事，但没做
may/might have done可能做
过某事;
should/ought to have done
shouldn’t have done
needn’t have done过去本来没
必要做,但做了，“本不必要”