什么是情态助动词?情态是什么个概念?

什么是情态助动词?情态是什么个概念?
什么是情态助动词?
情态是什么个概念?

什么是情态助动词?情态是什么个概念?
情态动词惊讲
,在英文中主要用来表示说话人的看法、态度等.它很接近中文里的能愿动词.从用法上来说,它有这样几个特点：
1）各个情态动词自身都有一定的词义.
2）情态动词不能在句中独立担当谓语.
3）情态动词在句中不受任何人称,性,数变化的影响.
4) 情态动词后接的不定式（除ought外）都不带to ,即接动词原形.
英文中的情态动词主要有：can , could ; may , might ; must ; ought ; need ; dare , dared ,另外,shall , will , should , would在一定的场合也可用作情态动词.例如：
He can speak five languages .他会说五种语言.
She must have arrived home by now .现在她准到家了.
We should study hard for our motherland . 我们应该为祖国而努力学习.
They needn't be in such a hurry for there is enough time
for them . 他们还有足够的时间,用不着这么慌张.
1. 常用情态动词的基本用法
can , could 能,会
（could可以看作是can的过去式,这两个词除了时态不相同外,在表达意思的许多方面是相同的.当然could也有自己独特的用法.）
1）表示脑力或体力上的能力
Nobody can stop the development of science .
谁也无法阻止科学的发展.
She can sing that song in English.她能用英文唱那歌.
He can submerge to a depth of about twenty meters .
他能潜入约二十米深的水中.
He could hardly support his family before he found the new job .他在找到那份新工作前几乎无 法养家.
I could not understand the lecture on the computer given by Mr. Smith .
我听不懂史密斯先生作的那个关于计算机的讲座.
2)表示客观上的可能性
You can borrow this useful book from the library .
你可以从图书馆借到这种有用的书.
A more suitable person than him for the job can not be found . 不可能找到比他更适合这份工作的人了.
Now people can skate on the lake .现在人们可以在湖上滑冰了.
When the storm stopped , the plane could take off .
当风暴停下来时,飞机可以起飞了不得.
3)表示主观上的允许
Can I ask you some questions about it ?
我可以问你有关这件事的几个问题吗?
You can not leave here till I come back .直到我回来你才能离开.
Such kind of thing can't happen any more later .
这类事以后不准再发生了.
Can you tell me how to get to the airport ? 你能告诉我怎么去机场吗?
Could you tell me how to get to the airport ?
您能告诉我怎么去机场吗?
Could I be forgiven my negligence ? 请原谅我的疏忽,行吗?
4）（用于否定句、疑问句或感叹句中）表示猜测、怀疑或惊诧
How can / could you be here ? 你怎么会在这儿?
She couldn't / can't be so stupid to do that .
她不可能蠢得去做那种事吧.
He couldn't / can't be over seventy .他不可能有七十多岁了.
Where could / can the boy be now ? 那孩子现在能在哪儿呢?