[语法初识]

原句感知 自主探究 ①Festivals can also be held to honour famous people.

②Some festivals are held to honour the dead or to satisfy the ancestors, who might return either to help or to do harm.

③Most ancient festivals would celebrate the end of cold weather, planting in spring and harvest in autumn.

④For the Japanese festival Obon, people should go to clean graves and light incense in memory of their ancestors. 以上四个句子都使用了情态动词。其中，句①中的can表示许可，意为"可以"；句②

中的might表示推测，意为"可能会"；句③中的would表示过去习惯性动作，意为"过去常会"；句④中的should表示劝告或建议，意为"应该"。 　　

　　[语法剖析]

语法点一 基本特征 　　1.情态动词有一定的词义，不能单独作谓语，需和实义动词或系动词一起作谓语。

　　The idea that computers can recognize human voices surprises many people.

　　电脑能识别人的声音，这种想法使很多人感到吃惊。

　　They must be in the classroom.

　　他们一定在教室里。

　　2．情态动词一般无人称和数的变化，个别情态动词有现在时和过去时两种时态变化。

　　Mary can speak three languages.

　　玛丽会说三种语言。

　　I could drive a car before I left school.

　　毕业前我就会开车。

3．构成否定句时，not放在其后面。