内容正文:
WG
情态动词
一、定义
二、特点
三、用法:can/could/be able to
may/might
must/have to
need
had better
dare
will/ would
shall/should/ ought to do
四、否定的特殊回答
五、推测总结
六、情态动词+have done
一、定义
表示说话人情感和态度的词。
二、特点
(一)有含义,和谓语动词一起构成谓语
(二)无人称和数的变化
(三)否定句在情态动词后+not
(四)疑问句将情态动词提前
三、用法
(一)can/could
1.能力(could 是can的过去式)
Mary can speak English fluently now.
Mary could speak English fluently 5 years ago.
!can 与be able to
(1)can 与 be able to 都表示能力,在许多情况下可以交替使用。 但can 只有现在式和过去式(could),而be able to 则有更多的形式。
(2)表达将来的能力,一般要用will be able to。
(3)be able to 的过去式 was/were able to 在肯定句中可表示过去设法做成了某事,相当于managed to do,而could 则无此意义。
三、用法
(一)can/could
2.请求和许可(could表示委婉,不是过去式,但回答用can)
Could/Can you do me a favor?
3.推测:可能(can’t 不可能)
Jimmy can’t stay in the classroom, I saw him just now.
(二)may/might
1.请求和许可(不用might)
2.推测:可能、也许
(1)把握不大
(2)might 比may 的可能性还小
(3)may not/ might not 表示“可能不” (can’t/couldn’t 表示“不可能”)
Don’t go any closer — it might not be safe.
3.祝愿 (多用于祈使句)
May you succeed!
(三)must
1.命令,强烈建议“必须”mustn’t “禁止”
You mustn’t smoke here.
2.推测:一定
He must be nearly 90 years old now.
3.表示“偏要,偏偏”,常指不愉快的事。
If you must go,at least wait until the storm is over.
(三)must
4. must/ have to do (不得不)
(四)need
1.情态动词:“需要”,没有人称和数的变化
You needn’t finish that work today.
2.实义动词:有人称和数的变化,否定式和疑问式要借助助动词do/does/did
sb. need to do sth. 某人需要做某事(主语与do 为主动关系)
sth. need doing/to be done 某事/ 某物需要被……(主语与do 为被动关系)
I need to have a rest.
The bike needs repairing.=The bike needs to be repaired.
(五)had better
劝告或建议:“最好”否定形式:had better not “最好不”
We had better not just talk and let’s help them.
(六)dare
1.情态动词:“敢”,没有人称和数的变化
Dare you tell her the truth?
2.实义动词:有人称和数的变化,否定式和疑问式要借助
助动词do/does/did
He didn’t dare(to)say what he thought.
(七)will /would
1.助动词
(1)will (一般将来时)
(2)would (过去将来时)
2.情态动词
(1)will :意志、决心、请求
(2)would: 意愿、许可、请求
Would you like to do...? 你愿意做...
Would rather do A than do B 宁愿做A,不愿做B
(八)shall/should/ought to
四、否定的特殊回答
Can you...? yes, I can/can’t.
May I...?yes, you can/can’t/mustn’t
Must I...?yes, you must/needn’t
Need I...?yes, you must/needn’t
needn’t= don’t have to=haven’t got to do
五、推测
(一)形式
1.情态动词+动词原形(对现在的推测)
2.情态动词+be doing(对正在进行的推测)
3.情态动词+have done(对已发生的推测)
(二)强弱
Must 一定
Will 一定
Would 应该
Should 应该
Can 可能
Could 可能
May 可能
Might 也许
六、情态动词+have done
真实语境(对过去的推测) 虚拟语气
must have done 过去一定做了 /
could have done 过去可能做了 本可能做但没做
may have done /
might have done 本可能发生但实际没发生
can’t have done 绝不可能做过 /
would have done 过去将来完成时 本来会做而没做
should have done / 本应但没做
ought to have done
needn’t have done 本没必要做但做了
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