(
课件网) Unit 6 Electricity everywhere 主题范畴： 人与自然；人与社会 主题群： 环境保护；科学与技术 子主题： 环境污染及原因，环保意识和行为；科学技术与工程，人类发明与创造 Key question What role does electricity play in our daily lives understand why electricity is important. explain different ways of producing electricity. observe safety rules for using electricity. talk about how to save electricity. Unit objectives 单元目标 I can: Lead in Game time What can you do Tell the student behind you and ask if he/she can do it. The next student should repeat this with another student. Example: No, I can’t. I can sing. Can you sing Yes, I can. I can … Can you … I can swim. Can you swim Modal verbs 情态动词 can cannot (can’t) may may not must must not 情态动词具有一定的词义，但不能独立存在，须与动词原形一起构成谓语，表示说话人对动作的观点，如意愿、需要、可能或怀疑等。情态动词有时态的变化，但没有人称和数的变化（have to除外）。 Model verbs 情态动词 Modal verbs: can and cannot, may and may not, must and must not Presentation Daisy is telling her brother Benny about her science lesson. Read their dialogue and pay attention to the wordsin bold. Benny: How was your school day, Daisy Daisy: It was great. We learnt about electricity in our science class. Benny: Can you tell me what you know about electricity Daisy: We can’t see it powering everyday things but we can see it when there is a lightning storm. Benny: Right. Mum told me we mustn’t go outdoors during a storm. It’s dangerous. Daisy: Yes, that’s right. However, you can produce electricity safely by rubbing a ruler against your sweater. Look at me! Benny: Wow. That’s fun! May I try Daisy: Yes, of course. But you must give it back to me because it’s my favourite ruler! Modal verbs can be used to talk about ability, permission, obligation, etc. Work out the rule After modal verbs such as can, may and must, we use (the base form / the -ing form / the -ed form) of a verb. A can and cannot Can you tell me what you know about electricity We can’t see it powering everyday things but we can see it when there is a lightning storm. Yes, that’s right. However, you can produce electricity safely by rubbing a ruler against your sweater. Modal verbs 情态动词 We use the modal verbs can and cannot (can’t) to say we are able or unable to do something. Let’s sum up the rules! 情态动词can的用法 can ① be able to “能”，表示能力。 我可以唱一首英语歌曲。 I can / am able to sing an English song. ② 表示许可或请求对方允许，意为“可以”。 我可以用你的字典吗？ Can I use your dictionary ③ 过去式：could 我十年前就能做到那样。 I could do that 10 years ago. ④ 否定式：cannot = can’t Peter can speak English. 否定 → Peter can’t / cannot speak English. 一般疑问句 → Can Peter speak English （一般疑问句，提前情态动词） 特殊疑问句 → What can Peter speak ⑤ could是can的过去式，但表示请求许可时，could和can不表示时态的区别，只是could的语气更加委婉，用could提出的请求 ... ...
