英语助动词课件.ppt

1、,系动词,也叫连系动词。系动词本身有含义，但它不能单独做谓语，后面必须接表语，用来说明主语的状况、性质、特征等。一起构成主系表结构。,你还记得什么是表语吗？,表语： 由形容词、名词、介词短语担任,系动词,be动词：最常用的系动词 She is beautiful. I am a student. They are in the classroom. 表示感受的“感官动词”： look, taste, smell, sound, feel感官动词+adj.：He feels cold. become, turn, get,Be动词用法口诀,I是am, you是are, is 前面三个他（她，它）

2、 其它复数都用are am, is was过去式/ are were过去式/,情态动词,情态动词表示说话人情绪、态度和语气。 本身有词义，但词义不完全，不能单独作谓语，其后接动词原形一起构成谓语。 常见的有can(could), may(might), will(would), shall( should), must, have to, had better,注意 情态动词v.原,情态动词,情态动词没有人称和数的变化 He can speak English. He speaks English very well.,情态动词详解,can表示个人能力所及或可能性 may表示允许、请求及可能性

3、。用may提问，肯定回答一般是Certainly.或Yes, you may. 否定回答一般用cant, mustnt must表示必须、一定是(must be),例释,I can make kites. That cant be Mr. Baker. - May I ask you a question? - Certainly. Your glasses may be in your pocket. We must be careful when we cross the road. -Wheres Alex? - He must be at home.,must 问句的回答,must 表

4、示“必须” 的问句，肯定回答用must,否定回答用neednt. Must we clean the classroom this afternoon? Yes, you must. No, you neednt. No, you dont have to.,had better 最好做,had better + v.原 had better not + v.原 We had better go back to the station now. Youd better not speak because the baby is sleeping.,shall,shall 常用于第一人称，用在问

5、句中表示：征求意见 Shall we go to the supermarket this weekend?,should,should 表示“应该” We should speak to the old people politely. (adv. 有礼貌地）,need,1.实义动词：放在肯定句、疑问句和否定句中 need + sth. need to do sth. We need more chairs. We need to plant more trees. 2.情态动词：放在疑问句和否定句中 You neednt do it in such a hurry.,助动词,协助主要动词构

6、成谓语的动词叫助动词，它对谓语动词起辅助作用。被协助的词叫主要动词。助动词本身没有含义，不可单独使用。 常见助动词：be, do(does, did), shall, will, have(has) Tom doesnt like watermelons.,助动词的使用,助动词本身没有意义，它只是帮助主要动词构成谓语，表示问句、否定句、时态等。 1、表示时态 We will sing and dance at the party. 2、构成疑问句 Do you like collecting stamps? Did you study Chinese before you came to China? 3、与not合用，构成否定句 I dont want to visit that farm. They havent finished the work yet.,助动词do,根据时态、主语人称、数的变化，do/does/did, 一般现在时：do, does(用于第三人称单数)，do用于其他人称， 一般过去时:did I dont like English. He doesnt do his homework at night. We didnt clean the room yesterday.,注意 do, does, did + v