新概念英语成人版第二册 Lesson17课件.ppt

* Key structures 情态动词must must 主观 必须 have to 客观 have got to 客观 现在must do  表推测 过去must have done * eg. 你必须少抽些烟。 You must cut down on smoking. I’m afraid I must go now. eg. Must you leave now? Yes, I must./ No, I needn’t. * Key structures must与have to一般可互换，但表示“必须” 时， must着重说明主观看法， have to比较强调客观需要。 eg. I must tidy up the room. 我必须打扫一下房间。（主观想法） I have to tidy up the room. 我不得不打扫一下房间。（客观需要） * Key structures have to有人称、数、时态的变化，而must没有eg. I had to go to see the dentist. She had to go shopping yesterday. 在否定结构中： don‘t have to　 表示“不必”　　　　　　mustn’t　　　　表示“禁止” eg. You don‘t have to tell him about it.　 你不一定要把此事告诉他。 You mustn‘t tell him about it.　　　　 你一定不要把这件事告诉他。 * Key structures must be可用来表示对现在情况的推测，（只有在肯定句中能这样用，这种揣测比may be表示的要肯定得多）： eg. He must be working in his office. She must be over forty. 试比较： eg. He must be staying there.　 他现在肯定呆在那里。 He must stay there. 他必须呆在那。 新概念英语成人版第二册 2023版课件 * A polite request from teachers If you make a mistake in your homework, your teacher will soon find it. You will be very unlucky if your teacher lets it go without any reminder. However, this does not always happen. Teachers are usually very careful. * During my studies in GuangWai, I found a note on my desk, “Miss./Mrs.,we welcome you to our English classes, but this is not a sleeping area. If you pay more attention to our wall signs, you will enjoy your stay here. This is only a reminder.” If you receive a request from your teacher like this, you can not fail to obey it. * * Have you realized that you are becoming older and older?Are you afraid of that? Do you want to keep/be always young? When you are trying to keep young, that means you are becoming older and older. If you are not afraid of becoming older and older , it shows you do think you are young enough. * Is it possible for us to keep/b