情态动词的情感用法
2013-06-09 10:28阅读：
can\ could\ be able to表示能力
can和be able to都表示能力(Ability)，意思上没多大区别。但can只有现在和过去时，而be able
to则有更多的形式。但当成功地完成某一具体动作时，通常不用could而用was/were able to来表示
must \ have to
Must 必须，应该，一定，准是，表示说话人认为有必要做某事，命令，要求别人做某事以及对事物的推测。
have to 客观必须
must 用来指
一般现在时和一般将来时，过去式可用 have to 的过去式代替。
I must finish my work today. 我今天必须完成我的工作。
Must I return the book tomorrow? 我必须明天还书吗?
After such a long walk, you must be tired. 走了这么长的路，你一定困了。
—
you interrupt now?
Can’t you see I’m on the phone?
—So
rry Sir, but it’s urgent. （2012重庆）
A.Can B.Should C.Must D.Would
If you smoke, please go
outside. (2011全国卷II,8)
A. can B. should C. must D. may
may\might
表示没有把握的推测；may放在句首，表示祝愿。：might 表示推测时，不表示时态。只是可能性比may 小。
may/might as well do sth 不妨做某事
would\used to
wouldn’t 总不肯
Days later, my brother called to say he was all right, but
say where he was.
（2012江苏）
A. mustn’t
B. shouldn’t
C. wouldn’t
D.
mightn’t
would可用来表示过去反复出现的动作（过去常常），但不能表示过去存在的状态，所以我们不能说：“she would be a
quiet girl.”
would强调过去某种特定情况习惯性的活动，是完全过去的事情，同现在没有联系。而used
to则着眼于过去和现在的对比，隐含现在已不存在，动作或状态都可表示；Would可以表示不规则的习惯，used to则不可
He used to be a naughty boy and cause trouble.
I used to get up at six in the morning.
Sometimes she would take a walk in the neighboring woods.
In those days, whenever I had difficulties, I would go to Mr. Chen
for help
should与ought to 表示“应该”时的区别
should 表示自己的主观看法，而ought
to的语气中，含有“按道理应该……”之意。若要反映客观情况或涉及法律义务和规定，一般用ought to。如：
You should help them with their work.
You are his father. You ought to get him to receive good
education.
should\shall
(1)shall（难点）
1)在疑问句中，shall用于征求对方的意见或请求指示，常用于第一、第三人称。
Shall we go out for a walk?
—The research on the new bird flu virus vaccine is challenging and
demanding. Who do you think can do the job?
—____ my students have a try?
A. Shall B. Must
C. Will D.
May
2)shall作为情态动词用于第二、三人称，表示说话人的意愿，有“命令”、“警告”、
“威胁”和“允诺”等意思。
如：You shall fail if you don't work harder. （警告） will
He shall have the book when I finish reading. （允诺） will
He shall be punished. （威胁） will
You shall do as I say. 按我说的做。（命令）must
You shall have my answer tomorrow. 你明天可以得到我的答复。（允诺）
He shall be sorry for it one day, I tell you.
有一天他会后悔的，我告诉你。（警告）
Nothing shall stop us from carrying out the plan.
什么也不能阻止我们执行这项计划。（决心）
—Will you read me a story ,Mummy?
—OK. You ________have one if you go to bed as soon as
possible.（陕西）
A. might B. must
C. could D.
shall
—I haven’t got the reference book yet, but I’ll have a test on the
subject next month.
— Don’t worry. You ____ have it by Friday.
A.could B.shall
C.must D.may
— What does the sign over there read?
—“No person _______smoke or carry a lighted cigarette，cigar or pipe
in this area．”[2007四川卷]
A．will B．may
C．shall D. must
(2)should
1) 表示劝告或建议，意为“应该”
2) 表示推测，用在肯定句中，对现在的情况或可能发生的事的主观推测或期待。意为“想必，大概，或许”
It should be a nice day tomorrow.
Try phoning Robert, he should be home now.
He should be around sixty years old.
3)
还可以用在if引导的条件句中，表示一件事听起来可能性很小，但也不是完全不可能，相当于“万一”的意思，从句谓语用should+动词原形构成
Ask Tom to ring me up if you should see him.
Should I be free tomorrow, I’ll come.
If things should change suddenly, please let me know
4）.用于疑问句或感叹句中，表示意外、惊异的情绪，意为“竟会”，与why，what
Why should anyone want to marry Tony?
Don’t ask me. How should I know?
4. 情态动词+完成式表示“本…却…”
“情态动词＋have＋过去分词 ”结构是情态动词专项考查的难点和重点，记住以下最常考查的结构：
（1）must have done “过去一定做了某事”
（2）can’t/couldn’t have done “过去不可能做了某事”
（3）may/might have done “过去可 能做了某事”
（4）needn’t have done “过去本来没有必要做而做了某事”
（5）could have done “过去本来能够做某事而没有做”
（6）should/ought to have done “过去本来应该做某事而没有做 ”
（7）shouldn’t/oughtn’t to have done “过去本来不应该做某事而做了”
