1、八年级英语上册Unit 1 现在完成时讲解与练习一、基本结构肯定句：主语 + have/has + 动词过去分词否定句：主语 + havent/hasnt + 动词过去分词疑问句：Have/Has + 主语 + 动词过去分词？回答：Yes, 主语 + have/has./ No, 主语 + havent/hasnt.（注：第三人称单数用 has，其他人称用 have。）二、核心用法过去动作对现在的影响：例：I have seen the film.I dont want to see it again.（看过电影现在不想再看）过去到现在已完成的动作：例：My aunt has travelle
2、d all over the world.（周游世界的动作已完成）三、时间状语just（刚刚）、already（已经，用于肯定句）、yet（还未，用于否定句 / 疑问句）。例：I have just heard the news./ Astronauts have already been to the moon./ The scientists have not heard from it yet.四、与一般过去时的区别现在完成时：强调动作对现在的影响，不接具体过去时间（如 yesterday, last week）。一般过去时：强调动作发生在过去，常接具体时间状语。例：I have jus
3、t been to London.I went there last month.五、不规则动词过去分词（需记忆）be been / do done / eat eaten / go gone / see seen / have had 等。六、针对性练习题1.句型转换（肯定句否定句 / 疑问句）原句：I have finished my homework.否定句：_疑问句：_回答：Yes, _./ No, _.2.选择助动词（have/has）She _ (have / has) visited the Great Wall twice.We _ (have / has) never bee
4、n to Japan.3.用 just, already, yet 填空They have _ arrived home.（刚刚）Have you called your mother _?（还未，疑问句）I havent finished my report _.（还未，否定句）4.翻译句子（现在完成时）我已经读过这本书了。你曾经去过长城吗？5.时态辨析（现在完成时 vs 一般过去时）用括号内动词的正确时态填空。I _ (visit) my grandparents last weekend.（强调过去动作）I _ (visit) my grandparents, so I know the
5、y are fine.（强调现在影响）6.不规则动词过去分词填空用所给动词的过去分词形式填空。He has _ (go) to the library.They have _ (see) that movie twice.7.完成句子（现在完成时）根据中文提示补全句子。他们已经学了五年英语了。They _ English for five years.我刚刚收到了他的来信。I _ his letter.8.改错（语法错误修正）He have lived in Beijing for 10 years.I have went to Shanghai last month.【答案解析】1.句型转换
6、否定句：I havent finished my homework.疑问句：Have you finished your homework?回答：Yes, I have./ No, I havent.2.选择助动词has（she 是第三人称单数）have（we 是第一人称复数）3.介词填空Just yet yet4.翻译句子I have already read this book.Have you ever been to the Great Wall?5.时态辨析visited（一般过去时，有last weekend）have visited（现在完成时，强调 “知道他们很好” 的现在影响）6.过去分词填空gone（go 的过去分词为 gone）seen（see 的过去分词为 seen）7.完成句子have learned/learnt have just received8.改错have has（He 是第三人称单数，用has）have went went（last month 是一般过去时标志，去掉have，用went）2
