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一、情态动词主要用来表示说话人的看法、态度等
1. can (could)
1)
表示能力,
could
主要指过去时间。例如:
①
Two eyes can see
more than one.
两只眼比一只眼看得清。
②
Could the girl read before
she went to school?
这女孩上学前能识字吗?
p>
因为
can
不能和其他助动词连用,所以表
示将来式时用
will be able to
例:
You will be able to skate
after you have practiced it two or three times.
p>
注意:
Can
表示一贯的能力
,
be able
to
表示客观能力和通过努力可以达到的能力
I
can’t swim. But I am sure I will be able to swim
through more practicing.
The fire spread
through the hotel, but everyone was able to get
out
2)
表示允许。例如:
①
Can I have a look at your
new pen?
我可以看一看你的新钢笔吗?
②
He asked whether he could
take the book out of the
reading
—
room.
他问他可不可以把书带出阅览室。
3)
表惊异、怀疑、不相信等态度。主要用于否定句、疑问句
或感叹句中。例如:
①
Where
can (could) they have gone to?
他们会去哪儿了呢?
②
How can you be so
careless?
你怎么这么粗心?
4)
比较委婉客气地提出问题或陈述看法。例如:
①
Can (Could) you lend me a
hand?
帮我一把好吗?
②
I’m afraid we couldn’t
give you an answer today.
恐怕我们今天不能给你答复。
Could/can+have done
结构表示对过去发
生的事情的
“
怀疑
”
< br>或
“
不肯定
”
< br>。
could
加完成式还用
于肯定句时
一般表过去可能完成而却未完成的动作。
Can they have won the basketball
match
?
他们赢了那场篮球赛吗?
What
you referred to just now can have made her very
sad.
你刚刚所谈到的可能令他很伤心。
You could have completed the task a
little earlier.
你本来能早点完成任务的。
(但事实上并没有提前完成任务)
I could have
passed my examination easily but I made too many
stupid mistakes.
我本可以轻易通过考试,但我犯了太多不该犯的错误。
如表具体做某一件事的能力时,则须用
be able to .
He was able to
translate the article without a dictionary.
他可以不用词典翻译那篇文章。
2
.
may
(might)
1)
表允许,
p>
might
可以指过去时间,也可指现在时间,语气更委婉。例如:
①
You may take
whatever you like.
你喜欢什么就拿什么。
②
May (Might) I ask for a
photo of your baby?
我可以要一张你宝宝的照片吗?
2)
在回答以
may
引起的问句时,多避免
用这个词,而用其它方式,如
Yes, please. / Certainly.
/ Please don’t. /
You’d better not. /
No, you
mustn’t.
等,以免显得太严峻或不客气。
3)may /might
推测性用法
可能
He may be may
not come today
(
可能不
)He may
/might come tomorrow.
注意
:
(1)
只用于肯定和否定句中
,
不用于疑问句中。
(2)
might
比
may
可能性更小
p>
He might get a
job.
He may get a job.
(3) may no
可能不
can not
不可能
He may not come .
He can’t come
4)
表建议(可和
as well
连用)
You may
(
might
)
as
well stay where you are.
你还是原地待着好。
(
may as well
有
“
还是
……
的好
p>
”
的含义)
5)
表祝愿
May you be happy!
6). might<
/p>
表过去的
“
可能
”
和
“
允许
”
多用于间接引语。
She said
that he might take her
dictionary.
她说他可以拿她的词典去用。
除在间接引语中外,
might
一般不表示过
去的
“
可能
”
与
“
许可
”
。
表过去的
“
可能
”
可用
could
,表过去的
“
p>
许
可
”
可用
were (was) allowed
to
。
7)might
表
现在的
“
可能
”
,其可能性要比
may
小。
Electric irons could be
dangerous; they might give you a severe shock.
8)may (might) + have +done
表
示对过去发生行为的推测,含有
“
想必
”
、
“
也许是
”
的意思。
It may have
been true.
这事也许是真的。
He might
not have settled the question.
他可能尚未解决那个问题。
3.
must
1)
表示义务。意为
“
p>
必须
”
(主观意志)
。例如:
We must do everything
step by step
.
我们必须按部就班地做一切事情。
Why must you always bother me?
为什么你偏要打扰我呢。
2)must be +
表语的结构,通常表示猜测,含有<
/p>
“
一定
”
之意。
(只用在肯定句中)
He must
be an honest
boy.
他一定是个诚实的男孩
This must be
your room.
这一定是你的房间。
3)must
的否定式有两个:
当回
答由
must
引起的问题时,
否定答复
要用
needn’t
或
don’t
have to
表示
“
不必
”
、
“
无须
”
、
“
用不着
”
、
“
不一定
”
的意义。当表示
“
不应
该
”
、
“
不许
可
”
、
“
禁止
”
时,就用
must
not
。
Must I go
tomorrow?
明天我必须去吗?
Yes,
please.
No , you needn’t.
4)must +have +
过去分词的结构,常用在肯定句
中,表示对过去发生行为的推测,含有
“
一定
< br>”
、
“
准是
”
的意
思。否定和疑问句用
can
。
She must have
studied English
before.
她以前一定学过英语。
5)
区别:
have to
的含义与
must
是很接近的
< br>,
只是
have to
比较强
调客观需要,
must
着重说明主观看法。
I must clean the
room.
(主观想法)
I
have to clean the
room.
(客观需要)
另外,
have to
能用于更多时态:
We had
to be there at ten
.
我们得在十点钟到那里。
We will have to
reconsider the whole thing.
have to
的否定式:
don’t have to do
表示
“
不必做
……”
之意。
1)
表征询意见,用于第一、第三人称疑问句。例如:
①
Shall I get you some tea?
我给你点茶好吗?
②
Shall the boy wait
outside?
让那男孩在外面等吗?
2)
表说话人的意愿,有
“
命令、允诺、警告、决心
”
等意思,用于第二、第三人称陈述句。
例如:
①
You shall do as I say.
按我说的做。
(命令)
②
You shall have my answer
tomorrow.
你明天可以得到我的答复。
(允诺)
③
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)
④
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)
< br>
5. should
1)
用
于第一人称疑问句中询问对方的意愿,但语气较委婉温和,如:
What should we do now?
我们现在该怎么办?
2)
表示应该、必须,常与
must
换用。例如:
We should
(must) master a foreign language at least.
3
)
(表示不确定)万一。例如:
①
If I should see him,
I'll tell him.
万一我见到他,我就告诉他。
②
If it should rain
tomorrow, the sports meeting would be postponed. <
/p>
万一明天下雨。
。
。
4)“should+be+
表语
”
的结构,表示推测或惊奇。例如:
They should be back by now.
他们现在应该回来了吧。
I am
sorry that she should be so careless.
我感到遗憾她竟会那样粗心。
5)“
should+have+
过去分词
”
的结构,
表示过去该做而实际上尚未做的动作或行为;
其否定则
表示发生了不应
该发生的行为。其同义结构
“ought to
have +
过去分词
”,
表示过去<
/p>
“
早应该
”
、<
/p>
“
本当
”
之意,
语气较强。例如:
I should have
thought of that.
这一点我是应当想到的。
(但没想到)
They should not have left so soon.
他们不应当走得这么早。
(但已走了)
6)
在
“It is
natural (strange, natural, necessary, surprised,
impossible, important ) that……”
句型中,
主语从句中的
谓语动词要用
should +<
/p>
动词原形
”
表示
“
理所当然
”
、
“
奇怪
”
、
“
必要
”
、
“
惊异
”
等的意思。
在
lest
(
以免)
、
for fear
(that) (
以防
)
、
in case
(以备万一)
等之后也要用
shoul
d+
动词原形
;
在
advise, sugest, order, demand, request
等
的从句中
should+
do”
例如:
It is
necessary that he(should) be sent there at once.
It is strange that he should say so.
他会说这样的话真是奇怪。
和
would
的用法
1
)表示意志,决心或愿望。例如:
Surely we will support all
the people in the world in their struggle for
peace.
He would not let me
try it .
他不肯让我去试。
2
)
will
表示经常性、习惯性、倾向性,
would
表示过去的习惯行为。
He will sit there hour
after hour looking at the traffic go by.
He would come to see me
when he was in Beijing.
3
)用于
第二人称作主语的疑问句中,表示对对方的请求,
would
的
语气比
will
委碗
Would/will you kindly tell me the way
to the station?
请问到火车站怎么走?
4
)表可能性
This will be the book you are looking
for.
这可能就是你要找的书。
She would be
about 60 when she died.
to
表义务,意为
“
应该
< br>”
(因责任、义务等该做)
,口气比
should
稍轻。例如:
①
You are his father. You
ought to take care of
him.
你是他父亲,应当管他。
②
You oughtn’t to smoke so
much.
你不应该抽这么多烟。
8.
used to
1
)表示过去的习惯动作或状态,现在不复发
生或存在。疑问式和否定式有两种。例如:
①
There used to be a
building at the street corner, but it has been
pulled down.
②
I usedn’t (didn’t use) to
smoke.
我过去不抽烟。
③
Used you (Did you use) to
go to school on foot?
你过去常步行去学校吗?
2
)
used to +v, be
used to +v-ing
和
be used to +v
used to +v
意为
“
过去常常
”
,
“
过去一直
”
;
be
used to +v-ing / n
(名词)意为
“
习惯于
”
;
be
used to +v
意
为
“
被用来(做某事)
”
。
例:
He
used to smoke. Now he doesn’t.
He’s quite used to hard work / working
hard.
The knife is used to
cut bread.
9.
特殊情态动词
need
和
dare
的用法:
p>
need
和
da
re
既可用作情态动词,也可用作实义动词。用作情态动词时,主要用于否定句和疑问句
。用作实
义动词时,可用于各种句式。
need
现在时
情态动词
You
need (not) do
He need (not)
do
过去时
实义动词
You (don’t)
need to do
He needs
(doesn’t need) to do
You
needed (didn’t need) to do
He needed (didn’t ne
ed) to
do
将来时
You need
(not) do
He need (not) do
dare
现在时
情态动词
dare to/
daren’t/dare not do
Dare he do?
过去时
dared
to/dared not do
Dared he do?
1)
用作情态动词。例如:
You
needn’t telephone him now.
She dare not go out alone at night.
她晚上不敢一个人出去。
2)
用作实义动词。例如:
You don’t need to do it yourself. I
dare say he’ll come
again.
我想他会再来(
I dare
say…
为固定
实义动词
dare/dares
to do
do/does not dare (to) do
Do you/Does he dear (to) do?
dared to do/did not dare (to) do
Did he dare (to) do
You will
(not) need to do
He will (not) need to
do
二、
情态动词表推测
:
表示可能(理论上或是逻辑判断上)
。例如:
①
He can’t
(couldn’t) have enough money for a new car.
他不可能有足够的钱买新车。
②
You mustn’t smoke while
you’re walking around in the wood. You could start
a fire.
在林子里走时勿吸烟,
那样可能会引起火灾。
p>
表可能(事实上)
。可以指过去时间,也可以指现在时间,但语气更
加不
肯定。
①
He may be at home.
他可能在家。②
She may
not know about it.
3. must
表
示揣测。意为
“
想必、准是、一定
”<
/p>
等,只用于肯定句。
①
He must be ill. He looks
so pale.
他准是病了。他的脸色苍白。
②
She’s wearing a diamond
necklace. She must have a lot of money.
4. should
表推测,意为
“
想必一定、照说应该、估计
”
等。例如:
①
The film should be very
good as it is starring first-class actors.
这部新电影是一流演员主演的,估计拍得很
< br>好。
②
They
should be home by now.
照说他们现在应当已经到家了。
5.
ought to
表推测,暗含很大的可能,语气较弱。例如:
①
Han Mei ought to know his
telephone number.
韩梅该知道他的电话号码。
②
There’
s a fine
sunset; it ought to be a fine day tomorrow.
今天有晚霞,明天应该是个好天。
6.
could
可能性不大,语气较弱。
7 might
可能性最小,语气最弱。
表示可能性大小的顺序为:
must
> will > would > ought to > should > can > could>
may>
might
7.
would rather, would
sooner, would (just) as soon, had rather, had
better, had sooner,
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