原句感知 自主探究 ①Today, both male and female athletes from around the world can take part.

②I am sure the whole of China must have felt proud when Xu Haifeng won the first gold medal for his country.

③Naturally, after I tell her what to do, my daughter must do the opposite!

④You should apologize to Mary for your rude remarks.

⑤Mr Jones must be a teacher, isn't he?

⑥He may come here by train, but I am not sure. (1)情态动词没有人称和数的变化。

(2)情态动词在句中虽有一定的词义，但不能单独作谓语，要和另一动词连用，构成谓语。(3)情态动词后面接动词原形，即不带to的不定式。 　　[语法剖析]

语法点一 基本概念 　　情态动词作为谓语的一部分，无人称和数的变化(have to除外)，一般不能单独使用，要与谓语动词构成完整谓语，不能单独作谓语，但在省略回答时，可单独使用。情态动词有can (could), may (might), must, have to, shall (should), will (would), dare (dared), need (needed), ought to等。

语法点二 基本用法 　　1.can (could)

　　(1)表示能力，can表现在的能力，could主要指过去的能力。

　　Two eyes can see more than one.

　　两只眼比一只眼看得多。

　　Could the girl read before she went to school?

　　这女孩上学前能识字吗？

　　(2)表示客观的可能(理论上或是逻辑判断上)。

　　He can't (couldn't) have enough money for a new car.

　　他不可能有足够的钱买新车。

　　You mustn't smoke while you're walking around in the wood. You could start a fire.

　　在林子里走时不要吸烟，那样可能会引起火灾。

　　(3)表示请求或许可。

　　当请求允许做某事时，两者均可用，但could语气更委婉。当表示允许某人做某事时，要用can而不用could。

　　Can I have a look at your new pen?

　　我可以看一看你的新钢笔吗？

　　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。

　　-Could I use your dictionary?

　　--我可以用一下你的词典吗？

　　-Yes, you can.

--可以，你用吧。