Unit4语法讲解及习题_现在完成时2025-2026学年沪教版英语（五四学制）七年级上学期

沪教英语（五四学制）七上Unit4语法讲解及习题 现在完成时 一、语法核心讲解 本单元重点语法：现在完成时（Present perfect tense） 1. 语法定义 现在完成时主要表达两种核心含义： 过去发生的动作对现在造成的影响或结果：不强调动作发生的具体时间，而强调其对现在状态的改变。 动作或状态从过去开始，一直持续到现在：表示一个动作或状态从过去某一时间开始，一直延续到现在，并且可能还会继续下去。 2. 基本结构 现在完成时的构成是：助动词 have/has + 动词的过去分词 (Past Participle)。 句型结构 构成形式 肯定句 主语 + have / has + 动词过去分词 否定句 主语 + have not / has not + 动词过去分词 (缩写形式：haven't / hasn't) 一般疑问句 Have / Has + 主语 + 动词过去分词 + 其他？ 肯定回答 Yes, 主语 + have / has. 否定回答 No, 主语 + haven't / hasn't. 注意： 当主语是第一人称 (I/We)、第二人称 (You) 或复数名词时，助动词用 have。 当主语是第三人称单数 (He/She/It) 或单数名词时，助动词用 has。 3. 动词过去分词构成规则 （1）规则变化 变化规则 例词 一般情况，直接在词尾加 -ed work → worked play → played 以不发音的字母 e 结尾，直接加 -d live → lived change → changed 以“辅音字母 + y”结尾，变 y 为 i，再加 -ed study → studied carry → carried 以重读闭音节结尾，且末尾只有一个辅音字母，双写末尾辅音字母，再加 -ed stop → stopped plan → planned （2）不规则变化（本单元高频） 动词原形 过去分词 be been have had see seen go gone make made break broken buy bought learn learned / learnt 4. 核心用法及时间标志词 用法一：过去动作对现在造成影响或结果 这种用法不强调动作何时发生，只强调现在的结果或状态。 常用时间标志词：already, yet, just, ever, never 单词 中文含义 位置 适用句型 例句（参考本单元） already 已经 句中（have/has 与过去分词之间） 肯定句 Smart homes have already changed our lives. yet 还；尚 句末 否定句、疑问句 But the smart home has not connected all smart devices yet. Have you seen this smart speaker yet? just 刚刚 句中 肯定句 Look! The smart fridge has just changed temperature. ever 曾经 句中 疑问句 Have you ever been to a smart home? never 从不 句中 否定句 I have never seen such a smart device. 用法二：动作从过去持续到现在 这种用法表示动作或状态从过去开始，一直延续到现在。 常用时间标志词：for, since, so far 单词 中文含义 用法 例句（参考本单元） for 长达 后接时间段，表示动作持续了多久 I 've had a sore throat for two days. since 自从 后接时间点或一般过去时的句子，表示动作从何时开始 She has lived here since 2015. She has lived here since she was five. so far 到目前为止 常置于句首或句末 So far, we have learned a lot about smart homes. 提问方式：对由 for 或 since 引导的时间状语提问，一律使用 How long...? 5. 现在完成时 vs. 一般过去时 时态 核心强调 时间标志词 例句对比 现在完成时 强调对现在的影响、结果或持续状态，与现在密切相关。 already, yet, ever, never, for, since, so far I have bought a smart speaker. (我已经买了一个智能音箱，现在我拥有它。) 一般过去时 强调动作在过去某个具体时间发生，与现在无关。 yesterday, last week, ago, just now, in 2020 I bought a smart speaker yesterday. (我昨天买了一个智能音箱，只说明昨天的动作。) 二、综合练习题 题型一：用所给动词的适当形式填空 1. I _______________ (finish) my homework already. 2. My father _______________ (not come) back home yet. 3. _______________ you ever _______________ (be) to a smart home? 4. We _______________ (learn) 500 new words so far. 5. She _______________ (live) in this city since she was five years old. 6. We _______________ (not see) each other for a long time. 7. Look! Someone _______________ (break) the window. 8. My grandparents _______________ (travel) to many countries in their life. 9. _______________ he _______________ (find) his lost key yet? 10. Smart homes _______________ (change) our daily lives greatly. 题型二：句型转换 1. I have already cleaned my bedroom. (改为否定句) I _______________ _______________ my bedroom _______________. 2. She has learned English for five years. (改为一般疑问句并作肯定回答) — _______________ she _______________ English for five years? — Yes, _______________ _______________. 3. They have visited the smart home. (对划线部分提问) _______________ _______________ they _______________? 4. We have known each other since 2018. (对划线部分提问) _______________ _______________ have you known each other? 5. He bought a new phone last month. (改为现在完成时) He _______________ _______________ a new phone for a month. 6. Have you ever been to Shanghai? (作否定回答) No, _______________ _______________. 7. The children have played computer games for two hours. (改为否定句) The children _______________ _______________ computer games for two hours. 8. My mother has made a cake for me. (改为一般疑问句) _______________ your mother _______________ a cake for you? 9. They have lived here for ten years. (对划线部分提问) _______________ _______________ have they lived here? 10. I have never seen such a smart device. (改为肯定句) I _______________ _______________ such a smart device. 题型三：单项选择 1. — _______________ you _______________ your homework yet? — Yes, I _______________ it ten minutes ago. A. Did; finish; finished B. Have; finished; have finished C. Have; finished; finished D. Did; finish; have finished 2. My uncle _______________ to London twice. A. has been B. has gone C. went D. goes 3. We _______________ any new smart devices since last year. A. don't buy B. didn't buy C. haven't bought D. won't buy 4. — How long have you _______________ this smart watch? — For two months. A. buy B. bought C. have D. had 5. The film is very interesting. I _______________ it twice. A. see B. saw C. have seen D. will see 6. — Where is your father? — He _______________ to the tech expo. He'll be back this afternoon. A. has been B. has gone C. went D. goes 7. I _______________ my keys, so I can't enter the house now. A. lose B. lost C. have lost D. will lose 8. They _______________ in this smart home for five years. A. live B. lived C. have lived D. are living 题型四：用 for 或 since 填空 1. I have had this smart phone _______________ two years. 2. She has learned English _______________ she was seven years old. 3. We have lived here _______________ 2015. 4. They have been friends _______________ a long time. 5. My father has worked in this company _______________ ten years ago. 三、答案与详细解析 题型一：用所给动词的适当形式填空 1. have finished 解析：already 是现在完成时肯定句的标志，主语是 I，所以用 have finished。 2. hasn't come 解析：yet 用于现在完成时的否定句，主语 my father 是单数，所以用 hasn't come。 3. Have; been 解析：ever 常用于现在完成时的疑问句中。 4. have learned / have learnt 解析：so far（到目前为止）是现在完成时的标志。 5. has lived 解析：since 引导的时间状语从句是现在完成时的标志，主语 she 是单数，所以用 has lived。 6. haven't seen 解析：for a long time 表示一段时间，是现在完成时的标志。 7. has broken 解析：强调“打破窗户”这个过去动作对现在造成的结果（窗户现在是破的），用现在完成时。 8. have traveled / have travelled 解析：in their life 表示“在他们的一生中”，常与现在完成时连用，表示经历。 9. Has; found 解析：yet 用于现在完成时的一般疑问句。 10. have changed 解析：强调智能家居对现在生活造成的影响，用现在完成时；主语Smart homes是复数名词，助动词用have。 题型二：句型转换 1. haven't cleaned; yet 解析：现在完成时变否定句，在 have/has 后加 not；already 用于肯定句，否定句和疑问句中要换成 yet 并放在句末。 2. Has; learned / Has learnt; she has 解析：现在完成时变一般疑问句，将 have/has 提到句首。肯定回答为 “Yes, 主语 + have/has”。 3. What have; done 解析：对动作“visited the smart home”提问，用疑问词 What。 4. How long 解析：对 since 2018（表示从过去到现在的一段时间）提问，用 How long。 5. has had 解析：buy 是短暂性动词，不能与表示一段时间的 for a month 连用，需要换成延续性动词 have，其过去分词为 had。 6. I haven't 解析：现在完成时一般疑问句的否定回答。 7. haven't played 解析：现在完成时变否定句，在 have/has 后加 not。 8. Has; made 解析：现在完成时变一般疑问句，将 have/has 提到句首。 9. How long 解析：对 for ten years（表示一段时间）提问，用 How long。 10. have seen 解析：去掉否定词 never，将句子变为肯定句。 题型三：单项选择 1. C 解析：yet 用于现在完成时；ten minutes ago（十分钟前）是明确的过去时间，用于一般过去时。 2. A 解析：has been to 表示“去过某地，现在已经回来了”；has gone to 表示“去了某地，现在还没回来”。句中“twice”（两次）表示去过并回来，所以选 A。 3. C 解析：since last year（自从去年以来）是现在完成时的标志。 4. D 解析：How long 提问，需要与延续性动词连用。buy 是短暂性动词，换成延续性动词 have，其过去分词为 had。 5. C 解析：twice（两次）表示“看过这部电影”这个经历，用现在完成时。 6. B 解析：根据答句“He'll be back this afternoon”可知，父亲现在不在这里，去了科技展还没回来，用 has gone to。 7. C 解析：强调“丢了钥匙”这个过去动作对现在造成的影响（现在进不了门），用现在完成时。 8. C 解析：for five years 表示动作持续了五年，从过去一直到现在，用现在完成时。 题型四：用 for 或 since 填空 1. for 解析：后接时间段 two years。 2. since 解析：后接一般过去时的句子 she was seven years old。 3. since 解析：后接时间点 2015。 4. for 解析：后接时间段 a long time。 5. since 解析：后接时间点 ten years ago。 ( 1 ) 学科网（北京）股份有限公司 $