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课件网) Unit 2 No Rules,No Order Section A What rules do we follow Grammar Focus (3a-3d) 注：学情不同，部分内容请老师根据提示及教学需求选上！ Learning Objectives In this lesson you will: 1. grasp the structures and the usage of imperative sentences; 2. be able to use modal verbs can, must, have to to talk about rules; 3. understand the signs of rules and explain what they mean. Watch and Say Watch the video and pay attention to the lines the characters say. What do they have in common Sit! Be careful! Donald, say something! Take a deep breath. Don’t ask me to change. Never send a sheep to kill a wolf. Let’s get out of here. Don’t be scared. ... begin with a verb short no subjects These sentences are called imperative sentences(祈使句)! Grammar Focus 祈使句（Imperative Sentences） 祈使句一般用来表示请求、命令、劝说、号召、警告等。祈使句的主语一般是第二人称you，但往往省略。祈使句的肯定式以动词原形开头，否定式在动词原形前加don't。 e.g. Just go along this street and turn left. Be careful when you cross the street. Practise the guitar every day. Don't be late for class. Don't fight. 祈使句的种类及构成 肯定的祈使句：动词原形+其他. e.g. Walk in the hallway. Stand up! Be polite. Keep quiet. Be a good boy. 否定的祈使句：Don’t+动词原形+其他. e.g. Don’t run in the hallways. Don’t litter! Don’t be late. let型祈使句：Let+第一/三人称+动词原型+其他. e.g. Let me tell you the way to my house. Let’s see the lions. Let him go. No型祈使句：No+名词/动名词. e.g. No parking. 禁止停车。 No photos. 禁止拍照。 No entry. 禁止进入。 Read the sentences. Do the verbs in bold need to change forms Why Walk in the hallway. Don’t run! Be polite and treat one another with respect. Don’t litter./You mustn’t litter. / You can’t litter. Can we bring our phones to class No,we can’t. We must keep them in our lockers. Can we eat snacks in class？ No,we can’t eat in class. We have to eat in the dining hall. 祈使句中的动词原型，不需要变换形式。 情态动词后用动词原型。 3a 情态动词（Modal Verbs） 情态动词表示说话人的语气和情态，如请求、许可、意愿、可能等。一般没有人称和数的变化。 情态动词本身不能单独作谓语，必须和动词原形连用。 情态动词的否定式一般是在其后加not构成，一般疑问句通常将它提到句首。 情态动词的肯定式一般不重读。 情态动词can 1. 表示能力（七上Unit 5已经学习） e.g. I can run fast, but I can’t swim. 2. 表示许可（本单元重点） e.g. We can play basketball at the weekend. Students can’t run in the hallways. Can we bring our phones to class 情态动词must 1. 表示“必须”（七上Unit 5已经学习），否定形式mustn’t 表示“禁止” e.g. Don’t arrive late for class. We must be on time. Students mustn’t use their phones at school. 2. 以must开头的一般疑问句，肯定回答用must，否定回答 用needn’t 或者don’t have to， 表示“不必要” e.g. —Must I clean the classroom now —Yes, you must./No, you needn’t/don’t have to. 情态动词 have to 表示“不得不；必须”,在表示“必须”时，与must意义接近， 有时可互换。 e.g. We have to be quiet in th ... ...
