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高中情态动词

[日期:11-03] 来源:网络  作者:未知 [字体: ]

高中情态动词——can

 can could

 

  1can表示能力,用在过去时中,could表示过去所具有的一般的能力;经常表示能够做某事,事实上不一定去做,而was / were able to则表示“过去做成了某事”(=managed to do, succeeded in doing)。在否定句中两者可通用。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?

 

  ③Mary can play the piano. She has been able to play it since she was 5.  玛丽会弹钢琴。她五岁起就会弹了。

 

  ④He could swim across the English Channel. But he didn't feel like it that day. 他能游过英吉利海峡,但那天他不想游。

 

  ⑤Yesterday I was able to get home before the heavy rain.  昨天我在下大雨前赶到了家里。

 

  ⑥He tried many times, then at last, with the help of his math teacher, he was able to work out the difficult problem.

 

  2、表示可能(理论上或是逻辑判断上),可用于肯定句,否定句和疑问句。can在肯定句中表“可能性”时是表示“理论(道理)上的可能性,普遍、一般情况下可能”,而不是表示具体某事发生的可能性;表示这样的意思时要用couldmaymightcan't couldn't)表示“不可能”,与must意义相反。

 

  ①Accidents can happen.意外情况是可能发生的。

 

  ②Scotland can be very warm in September.九月的苏格兰可以非常暖和。

 

  ③Will you answer the phone? It could may /might be your mother. 你去接电话好吗?可能是你妈妈打来的。(不能说It can be

 

  ④He can't couldn't have enough money for a new car.  他不可能有足够的钱买新车。

 

  ⑤You 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。

 

  ⑥When many people surf on the Internet, the speed can could be very slow.

 

  ⑦During rush hours, streets can could be vey crowded.

 

  ●can could have done表示对过去发生事情的推测,can have done只能用于疑问句和否定句中(“可能已经……了吗” “不可能已经”),肯定句中用“could have done”。

 

  ①Where can could he have gone?他会上哪儿去了呢?

 

  ②He can't couldn't have gone to school-it's Saturday.他不可能是去上学了,今天是星期六

 

  ③He could have gone off with some friends.他可能是和几位朋友出去了。(不说can have gone…)

 

  3、“could+完成式”还可用来表示虚拟(不用can)(也可表推测),“过去本能做而未做”以及用来责备某人在过去本可以做某事但未做。如:

 

  ①You were stupid to go skiing there you could have broken your leg. 你到那个地方去滑雪真傻,你可能会摔断腿的。

 

  ②You could have told me the boss was angry.你本该告诉我老板生气了。

 

  4、表示给予许可、允许或征求意见(=may)。

 

  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 readingroom.  他问他可不可以把书带出阅览室。

 

  ③You can take this book home to read more carefully.你可以把书拿回家更详细地阅读。

 

  5、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。

 

  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?

 

  6、比较委婉客气地提出问题或陈述看法。

 

  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。

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匿名 发表于 2012-2-7 13:03:11
This is very helpful!
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