内容正文:
第三讲 情态动词和虚拟语气
情态动词
1.情态动词的基本用法
情态动词
用法
例句
can/could
表示“能力”,意为“能,会”
Samuel, the tallest boy in our class,can easily reach the books on the top shelf.Samuel是我们班最高的男孩,他能轻易地拿到书架顶层的书。
表示推测,意为“可能”,用于否定句或疑问句中。can比could语气强
That can't be Mary—she is in London now.那不可能是玛丽——她现在在伦敦。
表示客观可能性,意为“有时候会”,用于肯定句
Credit cards provide us with lots of convenience, but sometimes they can lead to problems.信用卡给我们提供了许多方便,但有时候会带来一些问题。
表示礼貌地请求,意为“能,可以”。在疑问句中could可代替can, 语气更委婉
Can you tell us your recipe for happiness and a long life?你能告诉我们你幸福和长寿的秘诀吗?
用于固定句式中:can't...too/enough“无论……也不过分”“越……越好”
I can't thank you too much for all your help to my son while we were away from home.我非常感谢你在我们不在家时对我儿子的帮助。
may/
might
表示许可和请求,在疑问句中might比may的语气更委婉
Might/May I have a word with you? It won't take long.我可以和你说句话吗?不会耽误很长时间。
表示推测,意为“可能,或许”,通常用于肯定句和否定句中
If you forgot to turn it off when you went away, you might burn down the house.当你离开时如果忘记关掉它,你可能把整个房子都烧毁了。
用于固定句式:may/might as well+动词原形“不妨;倒不如……”
Since it is raining hard,you may/might as well stay here.既然雨下得这么大,你倒不如待在这儿。
must
表示义务、必要性等,意为“必须”。其否定式mustn't 意为“禁止”
—Can't you stay a little longer?——难道你不能再多待一会儿吗?—It's getting late.I really must go now.My daughter is at home alone.——时间不早了。现在我确实得走了。我的女儿独自一人在家。
表示猜测、推测,意为“想必,一定”。常用于肯定句中
You must be Carol.You haven't changed a bit after all these years.你肯定是卡罗尔。这么多年后你一点都没变。
表示偏执,固执,意为“非得,偏要”
If you must go, at least wait until the storm is over.如果你非要走,至少要等到暴风雨停了。
shall
用于第一、第三人称疑问句中,表示说话人征求对方的意见或向对方请示
Shall I tell Brett to come over straight after school tomorrow?要我告诉Brett明天放学后直接过来吗?
用于第二、第三人称陈述句中,表示说话人给对方的命令、警告、允诺或威胁
One of our rules is that every student shall wear the school uniform while at school.我们的规定之一就是每名学生在校期间都必须穿校服。
should
表示劝告或建议,意为“应该”
I don't think you should give up the opportunity to go to university which you have been dreaming about.我认为你不应该放弃你一直以来梦想的上大学的机会。
表示推测、可能性或预期,意为“应该;可能”
He should be here on time—he started early enough.他应该按时到这里的——他很早就出发