Unit3语法专项课件- 前缀re-+现在完成时Ⅱ2026-2027学年仁爱科普版英语九年级上册

该初中英语课件聚焦前缀re-构词法（含"重新/再次""返回/往复"两层含义及核心词汇）与现在完成时Ⅱ（for/since用法、短暂动词转延续短语），通过环保主题词汇导入，以词汇表、例句精讲搭建基础，衔接现在完成时回顾与拓展，形成从词缀到语法的学习支架。 其亮点在于融合语言能力与思维品质培养，如re-词汇结合环保例句（如"We reuse cloth bags"）提升情境表达，for/since对比表格及短暂动词转换清单（如join→be in）培养分析比较能力。采用分层练习（专项到综合）与易错点汇总，助力学生掌握学习策略，教师可直接用于课堂精讲与巩固，提升教学效率。

教学课件 仁爱英语九年级上册 Unit3 语法专项 ——前缀re-+现在完成时Ⅱ 全解精讲+分层练习 1 1.掌握前缀 re - 两层核心含义，熟练动词变形 2.熟记 re - 高频单词，能用于填空、写作 3.分清 for（时间段）与 since（时间点）用法 4.掌握短暂性动词变延续性短语规则 5.完成选词、单选、句型改写、问答类习题 6.规避现完成时搭配 for/since 高频易错点 学习目标 模块一 前缀 re- 导入 re - 是高频动词前缀，加在动词词根前构成新词 两层核心词义：①重新、再次 ②返回、往复 本单元贴合环保主题，词汇多和回收、再造相关 词性变化：词根动词 + re- = 全新动词 做题技巧：看到 re - 优先翻译 “再、重新” re - 核心词汇表 1 原动词 变形词 释义 use reuse 重复使用 cycle recycle 回收利用 new renew 更新；重启 visit revisit 重访、再次参观 take retake 重新获取；补考 re - 核心词汇表 2 原动词 变形词 释义 write rewrite 重写、改写 build rebuild 重建 think rethink 重新思考 create recreate 重塑、再造 记忆技巧：词根词义不变，仅增加 “再次” 含义   re - 词义例句精讲 1 1.We reuse cloth bags instead of plastic ones. 译：我们重复使用布袋，替代塑料袋。 考点：reuse 表再次使用，贴合环保话题 2.Factories recycle waste metal to make new goods. 译：工厂回收废金属制造新产品。 re - 词义例句精讲 2 1.The town will rebuild old houses next year. 译：这座小镇明年将重建老旧房屋。 2.You should rethink your ways of saving energy. 译：你应当重新思考节约能源的方式。 3.She decided to rewrite her article about low-carbon life. re - 变形时态拓展要点 1.re - 动词时态变化和普通动词完全一致 2.rebuild 过去式 / 过去分词：rebuilt（特殊变形） 3.情态动词 will/can/should 后用 re - 动词原形 4.主语三单，一般现在时动词加 s：renews re - 专项练习 1 词形填空 1.We plan to _________ the old museum this holiday. (visit) 2.Please _________ your essay to fix all spelling mistakes. (write) 3.The city _________ its environmental rules last month. (new) 4.After flood, local people _________ their homes slowly. (build) revisit rewrite renewed rebuilt re - 专项练习 2 短文选词填空 词库：rethink, reuse, recreate, reduce Many students waste lots of paper at school. 1.We need to _________ this bad habit and take action. 2.We can _________ blank paper on both sides. 3.This simple way can _________ paper waste greatly. 4.Small efforts help _________ a green school environment. rethink reuse reduce recreate re - 专项练习 3 单句改错 划出错误单词，写出正确 re - 变形 1.We should use plastic bottles again, so we can reusing them. 2.The town rebuild the broken bridge after the heavy rain last year. 3.You’d better rethinked your plan about waste sorting. reusing → reuse（can 后接动词原形） rebuild → rebuilt（last year 用过去式） rethinked → rethink（had better 后用原形） 模块二 现在完成时 Ⅱ 课前回顾 现完成时基础结构：主语 + have/has + 过去分词 How long 提问动作持续多久，用 for/since 回答 核心难点：短暂动词不能搭配 for、since 两类标志：时间段 for；过去时间点 since for 用法详细讲解 for 后面接持续时长（时间段） 常用搭配：for three days /for half a year /for 10 months 例句：I have kept old cans for two years. 翻译：我保存旧罐子已经两年了。 适用场景：单纯描述动作持续多久 since 用法详细讲解 since 后接过去时间点，分三类情况 1.年份 / 日期：since 2019 /since July 2.时间段 + ago：since five years ago 3.一般过去时从句：since I left school 例句：He has recycled rubbish since 2021. for VS since 对比表格 单词 搭配内容 例句 for 时间段 for six months since 时间点 / 过去从句 since last summer 答题口诀：有 ago、年份、从句一律用 since     纯数字时长，直接选用 for   高频易错：短暂动词 vs 延续短语 for/since 必须搭配延续动词，短暂动词需转换 leave → be away；join → be in；buy → have；die → be dead 错误：I have joined the club for a year. 正确：I have been in the club for a year. 现完成时 for/since 例句 1.She has collected waste paper for four years.（for + 时长） 译：她收集废纸已经四年了。 2.We have protected the river since we learned environmental lessons. 译：自从学习环保课，我们就一直在保护河流。 现完成时练习 1 for/since 介词填空 1.My family has sorted waste _________ two years. 2.I have kept reusable bags _________ last spring. 3.They have planted trees _________ 2018. 4.We haven’t used plastic bottles _________ a month ago. for since Since since 现完成时练习 2 根据提示改写句子 用 for/since 改写，动词改为延续形式 1.He joined the environmental group last year.（for one year） 2.She bought this recycling box three months ago.（since three months ago） He has been in the environmental group for one year. She has had this recycling box since three months ago. 现完成时练习 3 单项选择 1.—How long have you lived here? —_________ 2020. A. For B. Since C. In 2.I _________ this book for two weeks. A. buy B. have bought C. have had 3.They have stayed in the countryside _________ half a year. A. since B. for C. ago 4.He has been away _________ three days ago. A. for B. since C. at 5.How long _________ you _________ the green team? A. have; been in B. have; joined C. did; join B C B B A 现完成时练习 4 句型问答，根据问句和提示，完整写出答句 1.How long has Tom reused cloth bags? (two years) 2.How long has your grandma recycled waste? (five years ago) 现完成时练习 5 单句改错，划出错误并改正，重点短暂动词、for/since 1.I have left my hometown for five years. 2.They have join the recycling club since last term. 3.She has this bike since one year. I have reused cloth bags for two years. My grandma has recycled waste since five years ago. left → been away join → been in has → has had 现完成时练习 6 汉译英 1.我坚持垃圾分类已经三年了。 2.自从去年夏天，我就开始回收塑料瓶。 3.他加入环保社团一年了。（转换延续短语） I have sorted waste for three years. I have recycled plastic bottles since last summer. He has been in the environmental club for a year. 综合混合练习 1 词形转换 结合 re - 构词法 + 现完成时填空 1.We _______________ (reuse) shopping bags for three years. 2.Workers _______________ (rebuild) the park since last flood. 3.You need _______________ (rethink) your waste sorting habits. 4.She _______________ (recycle) paper since she was 12. have reused have rebuilt to rethink has recycled 综合混合练习 2 短文填空 选用 re - 变形、for/since、延续动词完成短文 I (1)_______________ (recycle) rubbish (2)_________ 2022. We (3)_____________ (reuse) bottles (4)_________ four years. We should (5)_________ (rethink) our lifestyle and (6)_________ a clean world. have recycled since have reused for rethink recreate re - 构词法易错点汇总 1.rebuild 过去式特殊变形 rebuilt，不可写 rebuilded 2.情态动词、to 后接 re - 动词原形 3.一般现在时三单主语，动词加 s：reuses 4.re - 只改变词义，不改变原词时态变化规则 for & since 易错点汇总 1.“时间段 + ago” 属于时间点，只能搭配 since 2.for 后面不能接年份、过去从句 3.短暂动词（join/leave/buy）不能直接搭配 for/since 4.How long 问句回答，两种介词不可混用 短暂动词转换记忆清单 join → be in；leave → be away buy → have；die → be dead begin → be on；borrow → keep 做题第一步：看到 for/since 立刻检查动词是否延续 单元语法重点总结 1（前缀 re-） 1.re - 两大含义：重新；返回 2.掌握 9 组核心 re - 变形动词 3.熟练变形时态，用于填空、写作 易混点对比复盘 1.reuse（重复使用）vs recycle（回收再加工） 2.for 5 years vs since 5 years ago 3.have joined（错误）vs have been in（正确） 4.rebuild（重建）vs rewrite（重写）词义区分 单元语法重点总结 2（现完成时 Ⅱ） 1.for + 时间段，since + 过去时间点 2.How long 提问持续时长专用搭配 3.短暂动词必须转为延续性短语 4.区分两类介词，完成单选、句型改写 解题通用步骤 1.构词题：先看词根，加 re-，再变时态 2.for/since 题：先判断是时间段还是时间点 3.现完成时长句：第二步检查动词是否延续 4.改错：优先查找介词、动词变形两处错误 课堂整体小结 1.吃透前缀 re - 构词规则与全部高频单词 2.分清 for、since 使用场景，不会混淆 3.牢记短暂动词转延续短语固定搭配 4.熟练完成填空、单选、改写、翻译全题型 教学课件 Unit3 语法专项 ——前缀re-+现在完成时Ⅱ Thank you for listening! 33 $