中职英语第三册unit 3 resources and environment.ppt

1） 标志词: already: yet: 多用于陈述句，位于have/has后，有时位于句末。 e.g. I have already finished my homework. 用于疑问句和否定句，位于句尾。 e.g. Have you found your lost book yet ? I havent had breakfast yet. ever : never: 多用于疑问句，问初次经历。 e.g. Have you ever been to Beijing? 用于否定句，位于have/has后 e.g. He has never argued with other people. just : before: 多用于陈述句，位于have/has后 可用于各句式，位于句尾。 e.g. Lucy has just washed her clothes. e.g. He hasnt been abroad before. 2）无标志词的： e.g. He is not feeling well now. He has caught a cold. I have lost the key. I cant go into my room. Exercises 1. I ________(have) lunch already. 2. Has the train_______ (arrive), yet? 3.Tome ____ never_______ (be to ) China. 4. The twin ______just _____(see) my father. have had arrived has been to has seen eg: We have lived in this city for ten years. He has been there in the rain for an hour. She has taught in this school since two years ago. We have known each other since we met. 2.表示开始于过去并持续到现在的 动作. ( 动词：延续性，时间：到现在) 标志词: 1）for +一段时间e.g. We have lived in this city for ten years. 2）since +过去点时间 since +一段时间+ago since +从句（从句用一般过去式） 3） so far, once/twice/ three times ,all ones life e.g. They have learnt 2000 words so far. Tom has seen the film twice. Her father has worked in the factory all his life. 4） in the past +一段时间 during the last +一段时间 e.g. They have built many high buildings in the past three years. Great changes have taken place in my hometown during the last two years I’ve been here since 1999. She’s been there for an hour. for: 引导的短语表示一段时间，如：for ten years since：引导的短语表示时间点，意为“自从…以来”，如since 1982 练习：请在下列时间前填上for或 since： 1. ______ ten months 2. ______ 1995 3. ______ five years 4. _______ 3 minutes ago 现在完成时和一般过去时的区别： 现在完成时，强调这一动作产生的结果对现在的影响，与现在有关。 一般过去时，仅仅表示在过去某一时刻曾发生过这一动作，与现在无关。 have / has been to