Unit7语法讲解及习题：现在完成时 (Present Perfect Tense)-2025-2026学年沪外教版英语七年级上册

沪外教版英语七上Unit7语法讲解及习题 现在完成时 (Present Perfect Tense) 一、语法详细讲解 结合沪外教版七上Unit7 "Global warming" 教材内容，本单元核心语法为 现在完成时，用于描述过去发生的动作对现在造成的影响或结果，以及从过去持续到现在的动作或状态。 语法点一：核心概念与用法 1. 核心定义 表示过去发生的动作对现在造成的影响或结果。 例：The ice has started to melt earlier each year.（冰每年开始融化得更早了。——对现在的影响：北极熊无家可归） 表示从过去持续到现在的动作或状态。 例：Some polar bears have lost their homes.（一些北极熊已经失去了它们的家园。——状态持续到现在） 2. 结构公式 肯定句：主语 + have/has + 动词过去分词 (V-ed) 否定句：主语 + haven't/hasn't + 动词过去分词 (V-ed) 一般疑问句：Have/Has + 主语 + 动词过去分词 (V-ed)? 3. 时间标志词 already（已经）：用于肯定句，例：I have already finished my homework. just（刚刚）：用于肯定句，例：He has just left. yet（还、仍）：用于否定句和疑问句，例：I haven't seen him yet. / Have you finished yet? 语法点二：动词过去分词的构成 1. 规则动词 一般加 -ed：finish → finished, watch → watched 以不发音的e结尾加 -d：live → lived, hope → hoped 以“辅音字母+y”结尾，变y为i加 -ed：study → studied, carry → carried 重读闭音节双写末尾辅音加 -ed：stop → stopped, plan → planned 2. 不规则动词（教材高频） 原形 过去分词 原形 过去分词 be been是 lose lost失去 do done做 go gone去 have had有 see seen看见 make made制作 get got得到 write written写 cut cut砍、切 二、语法专项习题 第一部分：用 already, just, yet 填空 1. The sea level has ___________ risen a lot because of global warming. 2. I have ___________ heard the news about the terrible wildfire. 3. The growing population has ___________ created a lot of carbon dioxide (CO₂). 4. Scientists around the world haven't come up with a good idea to solve the problem ___________. 5. Global warming has ___________ made seawater warmer and warmer. 6. Have they found the causes of climate change ___________? 7. I have ___________ finished reading the book about global warming. 8. He hasn't called me back ___________. 9. We have ___________ planted many trees to fight against pollution. 10. Have you ever been to the Great Barrier Reef ___________? 第二部分：用所给动词的正确形式填空 11. Factories ___________ (burn) a lot of fuels such as oil and gas. 12. More and more cars ___________ (produce) a lot of gas into the air too. 13. The greenhouse gases ___________ (catch) a lot of heat from the sun. 14. People ___________ (cut) down forests for wood for years. 15. Many forests ___________ (become) farmland or roads. 16. I have already___________ (read) an article about carbon footprints. 17. We have just ___________ (walk) to get around. 18. In recent years, we ___________ (drive) cars to work. 19. Heating or cooling a house with electricity ___________ (be) normal. 20. Our daily actions ___________ (put) a lot of harm to our planet. 第三部分：单项选择 21. —___________ you ___________ the new film? —Not yet. I'll see it this weekend. A. Did; see B. Have; seen C. Do; see D. Will; see 22. The ice ___________ to melt earlier each year because of global warming. A. start B. started C. has started D. is starting 23. Some polar bears ___________ their homes. A. lose B. lost C. have lost D. are losing 24. I ___________ just ___________ a book about global warming, so I can tell you something about it. A. have; read B. has; read C. did; read D. do; read 25. —Have you finished your homework ___________? —Yes, I ___________already finished it . A. yet; have B. already; have C. yet; did D. already; did 26. He ___________ never ___________ to Australia. A. have; been B. has; been C. did; go D. will; go 27. The population of the world ___________ very fast in recent years. A. increase B. increased C. has increased D. is increasing 28. We ___________ already ___________ many trees to protect the environment. A. have; planted B. has; planted C. did; plant D. do; plant 29. —___________ you ever ___________ to a climate change conference? —No, I haven't. A. Did; go B. Have; been C. Do; go D. Will; go 30. The Earth's temperature ___________ a lot over the past 100 years. A. rise B. rose C. has risen D. is rising 第四部分：句型转换 31. I have read the book about global warming.（改为否定句） I ___________ ___________ the book about global warming. 32. He has just finished his homework.（改为一般疑问句并作否定回答） —___________ he just finished his homework? —No, he ___________. 33. They have already planted many trees.（改为否定句） They ___________ planted many trees ___________. 34. The sea level has risen a lot because of global warming.（对划线部分提问） ___________ ___________ the sea level risen a lot? 35. I have never been to the Great Barrier Reef.（改为同义句） I ___________ never ___________ to the Great Barrier Reef. 三、答案及详细解析 第一部分：用 already, just, yet 填空 1. already 解析：肯定句，表示“已经”。 2. just 解析：肯定句，表示“刚刚”。 3. already 解析：肯定句，表示“已经”。 4. yet 解析：否定句，表示“还、仍”。 5. already 解析：肯定句，表示“已经”。 6. yet 解析：疑问句，表示“还、仍”。 7. already/just 解析：肯定句，两者均可。 8. yet 解析：否定句，表示“还、仍”。 9. already 解析：肯定句，表示“已经”。 10. yet 解析：疑问句，表示“还、仍”。 第二部分：用所给动词的正确形式填空 11. have burned 解析：表示过去动作对现在的影响，用现在完成时。 12. have produced 解析：同上。 13. have caught 解析：同上。 14. have cut 解析：for years表示动作持续到现在，用现在完成时。 15. have become 解析：同上。 16. read 解析：already 是现在完成时标志词，用现在完成时。 17. Walked 解析： just是现在完成时标志词，用现在完成时。 18. have driven 解析：In recent years表示从过去持续到现在，用现在完成时。 19. has been 解析：动名词作主语，谓语用单数，用现在完成时。 20. have put 解析：表示过去动作对现在的影响，用现在完成时。 第三部分：单项选择 21. B 解析：Not yet. 是现在完成时的典型回答。 22. C 解析：表示过去动作对现在的影响，用现在完成时。 23. C 解析：同上。 24. A 解析：just是现在完成时的标志，主语是I，用have。 25. A 解析：yet用于疑问句，already用于肯定句。 26. B 解析：never是现在完成时的标志，主语是He，用has。 27. C 解析：in recent years是现在完成时的标志。 28. A 解析：already是现在完成时的标志，主语是We，用have。 29. B 解析：ever是现在完成时的标志。 30. C 解析：over the past 100 years是现在完成时的标志。 第四部分：句型转换 31. haven't read 解析：现在完成时的否定句，在have后加not。 32. Has; hasn't 解析：现在完成时的一般疑问句，将has提至句首，否定回答用hasn't。 33. haven't; yet 解析：现在完成时的否定句，将already改为yet。 34. Why has 解析：对原因提问用why，现在完成时的疑问句将has提至主语前。 35. have; been 解析：have been to表示“去过某地”，与原句同义。 ( 1 ) 学科网（北京）股份有限公司 $