Part3[整理].ppt

Unit 12;The worst part about my job is that sometimes I have to work nights. I enjoy my work because I needn’t make decisions. I wish I could come here every day. It sounds like you might like to be a zookeeper. I think the worst part is that the work can be difficult and unpleasant. I think that clearing the litter box at home should be your chore now. Zoo animals must be kept in good condition.;情态动词本身有一定的词义,表示说话人的 情绪、态度或语气,但它们不能单独作谓语, 只能和行为动词原形一起作谓语,表示完整 的意思。 本单元我们主要接触的情态动词有: ;1. can和could (1) 表示能力, 意为“能, 会”。 Can you play tennis? (2) 表示提建议或请求。 Can you pass me that book? (3) 表示“许可,可以”, 常用于口语中。 You can use my bike. ;提示: could也可表示请求,它的语气比can委婉。 当could用于现在时和将来时, 语气更加客 气和委婉；也可用于表示可能性不大。 Could you help me? I wish I could fly like a bird.;2.may和might (1) 表示许可或征询对方许可。 May I use your dictionary? (2) 表示推测, 意为“可能, 或许”。 He may come tomorrow. ;提示： might是may的虚拟语气形式, 它表示较 多的怀疑，更加不肯定，语气更委婉。 He might come today.;3.must (1) 表示“必须”, 强调主观意愿或客观要求。 I must go now. You must finish it on time. (2) 表示“一定”, 表示一种可能性很大的推测, 一般用于肯定句中。 —There’s someone knocking at the door. —It must be Jim. ;提示: 表示“一定不, 不可能”, 常用can’t, 。 I saw him playing football just now. He can’t be in the classroom. ;(3) mustn’t意为“不要”,表示禁止或不允许。 You mustn’t sit on the stairs. (4) 以must开头的一般疑问句,肯定回答用must,否定回答要用needn’t。 —Must I return the book now? —No, you needn’t. / Yes, you must. ;4. have to have to 表示“不得不；必须”, 强调客观原因。 否定式用don’t / doesn’t have to。 My mother isn’t at home, so I have to cook by myself. ;5.should (1) should用于提出建议时,表示常理认为 是对的事或适宜做的事,意思是“应该”, 这 时它可以和ought to互换使用。 You should / ought to tell your mother about it at once. ;(2) should用于第???人称的疑问句中, 表示征询对方的意见, 语气较婉转。 What should we do? ;6.need (1) need意为“需要”,它既可作情态动词,也可作实义动词。 need 作实义动词,后面可接不定式或动名词作宾语。接不定式时表示主动,接动名词时有被动的含义,相当于不定式的被动语态。 You need to finish your work now. The window needs cleaning. = The window needs to be cleaned. ;(2) need作情态助动词,通常用于否定句 或疑问句中, 后面的动词用原形。 You need not worry about h