Unit 1 Festivals around the world (Period 3 Learning about language: Grammar)
4)情態動詞后接都不帶to的不定式（除ought外）, 即接動詞原形。
常用情態動詞的基本用法
1. can/could
1)表示腦力或體力上的能力
nobody can stop the development of science.
誰也無法阻止科學的發展。
she can sing that song in english. 她能用英文唱那首歌。
he could hardly support his family before he found the new job.
他在找到那份新工作前幾乎無法養家糊口。
i could not understand the lecture on the computer given by mr. smith.
我聽不懂史密斯先生作的那個關于計算機的講座。
2)表示客觀上的可能性
you can borrow this useful book from the library.
你可以從圖書館借到這種有用的書。
a more suitable person than him for the job can not be found.
不可能找到比他更適合這份工作的人了。
when the storm stopped, the plane could take off.
當風暴停下來時, 飛機可以起飛了。
3)表示主觀上的允許
can i ask you some questions about it?
我可以問你有關這件事的幾個問題嗎？
you can not leave here till i come back.
直到我回來你才能離開。
such kind of thing can’t happen any more later.
這類事以后不準再發生了。
can/could you tell me how to get to the airport?
你能告訴我怎么去機場嗎？
4)（用于否定句、疑問句或感嘆句中）表示猜測、懷疑或驚詫
how can/could you be here? 你怎么會在這兒？
she couldn’t/can’t be so stupid to do that.
她不可能蠢得去做那種事吧。
where could/can the boy be now?
那孩子現在能在哪兒呢？
另外, could還常用于表示客氣委婉的看法、提問以及用于虛擬語氣的結構中。這時could就不可以看作是can的過去式了, 而是could自己獨特的用法。例如:
could you speak a little slowly?
您能說慢一點兒嗎？
i’m afraid that we couldn’t give you any definite answer at this moment.
恐怕我們這時候還無法給予您確切的答復。
i could come earlier if asked.
如果要讓我早一點來, 我可以來早一點。
2. may/might
1)表示可能性
i may be busy from tomorrow on.
從明天起我可能會忙起來。
you may catch sight of the sunrise from here when you get up before 5 in the morning.
你在早晨五點鐘以前起來, 或許能從這兒看到日出。
i wondered if they might agree with the idea.
我想知道他們是否會同意這種想法。
she thought it might be wise to try her luck here.
她認為在這兒碰碰運氣也不錯。
2)表示允許
may i come in? 我可以進來嗎？
i’d like to have a smoke here if i may.
如果可以的話我想在這兒抽一支煙。
the librarian told her that she might return the book to the library in three days.
圖書管理員告訴她說, 她可以在三天后還那本書。
3)may用來表示祝愿
may that day come soon. 但愿這天早日到來。
may you succeed in winning the first prize in the game.
祝愿你比賽奪冠成功。
4)might也常用于一些狀語從句中或虛擬語氣的結構中
i could not convince him, try as i might.
我無論用什么樣的辦法也不能說服他。
they left off earlier on that day so that they might catch the first train.