Unit 4 The Wonders of Nature语法专题知识点及练习 2025-2026学年人教版英语八年级下册

Unit 4 The Wonders of Nature 一、核心语法 —— 知识点精讲（必背） 1. 现在完成时（核心必考，表经历） 用法：本单元重点考查现在完成时表“过去的经历”，即“曾经见过、去过或了解过某自然奇观”，贴合单元“自然奇观探索”主题，是描述自然景观经历的核心语法，也是书面表达和对话的高频考点。 标志词：ever（曾经）、never（从未）、already（已经，多用于肯定句）、yet（还；尚未，多用于否定句和疑问句末尾）、just（刚刚）、before（以前） 结构： 肯定：主语（三单） + has + 动词过去分词 + 其他；主语（非三单） + have + 动词过去分词 + 其他 否定：主语（三单） + hasn’t + 动词过去分词 + 其他；主语（非三单） + haven’t + 动词过去分词 + 其他 疑问：Has + 主语（三单） + 动词过去分词 + 其他？ / Have + 主语（非三单） + 动词过去分词 + 其他？（回答：Yes, 主语 + have/has. / No, 主语 + haven’t/hasn’t.） 本单元核心动词过去分词（必考，贴合自然奇观主题）： see → seen（看见）、visit → visited（参观）、find → found（发现）、create → created（创造）、survive → survived（存活）、remain → remained（保持） 例句（贴合单元话题）： ① I have ever seen the vast natural scene in the western desert.（非三单肯定句：我曾经见过西部沙漠那片广阔的自然景色。） ② She hasn’t visited the ancient cave with mysterious rocks yet.（三单否定句：她还没有参观过那座有着神秘岩石的古溶洞。） ③ —Has he found out the mystery of the natural wonder? —No, he hasn’t.（三单疑问句及回答：他解开那处自然奇观的谜团了吗？没有，还没有。） 2. 定语从句（重点必考，修饰自然奇观） 用法：用于修饰“自然奇观”相关的名词（如wonder, scene, rock, lake等），补充说明自然奇观的特征、位置或作用，贴合单元“描述自然奇观”的核心需求，是句型转换和书面表达的重点。 引导词：that/which（修饰事物，本单元主要修饰自然奇观类名词，可省略的情况：当引导词在从句中作宾语时） 结构： 主句 + 定语从句（先行词<自然奇观类名词> + that/which + 从句谓语 + 其他） 常见搭配（贴合本单元词汇）： 1. a natural wonder that/which attracts many visitors（一处吸引许多游客的自然奇观） 2. a rock that/which takes the shape of a bird（一块形似小鸟的岩石） 3. a lake that/which remains unknown for centuries（一个数世纪以来仍不为人知的湖泊） 4. a scene that/which is surrounded by mountains（一处被群山环绕的景色） 例句（贴合单元话题）： ① This is a natural wonder that/which has survived for more than 1,000 years.（定语从句修饰natural wonder：这是一处存活了1000多年的自然奇观。） ② We visited a cave that/which was formed by natural forces.（定语从句修饰cave：我们参观了一个由自然力量形成的溶洞。） ③ The rock that/which we saw yesterday looks like a lion.（引导词作宾语，可省略：我们昨天看到的那块岩石看起来像一头狮子。） 3. 情态动词may/might（表推测，重点必考） 用法：本单元用于“推测自然奇观的形成原因、特征或神秘现象”，may语气稍肯定，might语气更委婉、不确定，贴合单元“探索自然奇观奥秘”的主题，是口语和书面表达的易错点。 标志词：may（可能）、might（可能，语气更弱）、perhaps（或许）、maybe（或许） 结构（无人称和数的变化）： 肯定推测：主语 + may/might + 动词原形 + 其他（可能做某事） 否定推测：主语 + may/might + not + 动词原形 + 其他（可能不做某事，不可用may not/might not的缩写） 常见搭配（贴合本单元词汇）： 1. may/might take shape because of wind and rain（可能是由于风雨形成的） 2. may/might remain unknown for a long time（可能会长期不为人知） 3. may/might be formed under the water（可能是在水下形成的） 例句（贴合单元话题）： ① The strange rock may take shape because of wind erosion.（肯定推测：这块奇特的岩石可能是由于风蚀形成的。） ② The mystery of the lake might not be solved soon.（否定推测：这个湖泊的谜团可能不会很快被解开。） ③ Maybe the natural wonder may have existed since ancient times.（结合maybe，语气更委婉：或许这处自然奇观从古代就已经存在了。） 4. 介词短语（表方位/特征，重点必考） 用法：用于描述自然奇观的方位、状态或特征，是修饰自然景观的核心补充语法，常与定语从句、陈述句结合使用，贴合单元“描述自然奇观”的需求，也是书面表达的得分点。 核心介词及短语（贴合本单元词汇）： in（在……里面）、on（在……上面）、below（在……下方）、around（在……周围）、in front of（在……前面）、in depth（深入地）、by the lake（在湖边）、at the foot of the mountain（在山脚下） 结构：介词短语可位于句首、句中或句末，作状语或定语 例句（贴合单元话题）： ① There is a beautiful waterfall at the foot of the mountain.（作状语，表方位：山脚下有一处美丽的瀑布。） ② The fish swimming below the surface of the lake are very lovely.（作定语，修饰fish：在湖面下方游动的鱼非常可爱。） ③ We need to explore the cave in depth to find its secrets.（作状语，表方式：我们需要深入探索这个溶洞，找出它的秘密。） 5. 自然奇观类常用句型（易错重点） 用法：结合本单元核心语法，用于询问、描述自然奇观及推测其奥秘，是口语对话和书面表达的核心句型，贴合“自然奇观探索”的交流场景。 常用句型（必考）： 1. —Have you ever seen a natural wonder that takes a special shape? —Yes, I have. / No, I haven’t.（询问自然奇观经历+定语从句） 2. This is a vast natural scene which is famous for its unique beauty.（描述自然奇观特征+定语从句） 3. The natural wonder may have been created by powerful natural forces.（推测自然奇观形成+现在完成时被动） 4. There is a mysterious cave below the mountain that remains unknown.（描述自然奇观位置+定语从句） 6. 易错点辨析（贴合本单元语法）  现在完成时与一般过去时的区别：现在完成时（have/has + 过去分词）表“过去经历对现在的影响”，不与具体过去时间（如yesterday, last week）连用；一般过去时（动词过去式）表“过去发生的具体动作”，常与具体过去时间连用，如：I have seen the waterfall.（现在完成时，强调“见过”的经历）/ I saw the waterfall last month.（一般过去时，强调“上个月看到”的具体动作）  定语从句中that与which的区别：两者均可修饰自然奇观类事物，无本质区别；当先行词为the only one, the best等限定词时，只能用that，如：This is the only natural wonder that I have visited.（不可用which）  may与might的区别：may语气稍强，表“较有把握的推测”；might语气较弱，表“不确定的推测”，如：The rock may be 1,000 years old.（较有把握）/ The rock might be older than we think.（不确定）  介词below与under的区别：below强调“在……下方，不垂直”，贴合自然景观描述（如水下、山下）；under强调“在……正下方”，如：The fish are below the surface.（水下，不强调正下方）/ The bridge is under the waterfall.（瀑布正下方） 二、核心语法 —— 专项练习题（基础 + 提高） 一、用所给动词的正确形式填空 1. My parents __________ (visit) the Great Falls, a famous natural wonder, twice. 2. This is a rock that __________ (take) the shape of a rabbit after thousands of years. 3. —__________ you ever __________ (find) the mystery of the ancient cave? —No, I haven’t. 4. The natural wonder __________ (may) exist since ancient times, but we are not sure. 5. They __________ (not see) such a vast desert before; it’s their first time to visit it. 6. Nature __________ (create) many amazing wonders, and we should protect them. 7. The lake __________ (might) not be very deep, so we can swim in it carefully. 8. We __________ (already finish) learning the new words about natural wonders. 9. The cave that we __________ (explore) yesterday is full of beautiful stones. 10. Some rare plants __________ (survive) in the harsh desert for centuries. 二、单项选择 ( ) 1. —Have you ever seen a natural wonder that ______ many visitors? —Yes, I have. It’s very beautiful. A. attract B. attracts C. attracted ( ) 2. This is the most amazing natural wonder ______ I have ever visited. A. that B. which C. who ( ) 3. —______ I visit the mysterious cave with my friends this weekend? —Yes, you may. A. Should B. May C. Have ( ) 4. He ______ the natural wonder before, so he wants to visit it again. A. sees B. saw C. has seen ( ) 5. The fish swimming ______ the surface of the lake are very small but lovely. A. under B. below C. on ( ) 6. —Has she solved the mystery of the rock? —No, she ______. She is still trying. A. hasn’t B. doesn’t C. didn’t ( ) 7. The natural wonder ______ be formed by wind and rain, but I’m not sure. A. must B. may C. should ( ) 8. We visited a lake ______ is surrounded by green mountains. A. that B. who C. whom ( ) 9. He ______ not have seen the waterfall yet; he just arrived here an hour ago. A. may B. must C. should ( ) 10. There is a beautiful scene ______ the foot of the mountain. A. in B. at C. on 三、句型转换 1. I have seen a natural wonder that takes the shape of a bird.（否定句） I __________ __________ seen a natural wonder that takes the shape of a bird. 2. This is a natural cave that was formed by natural forces.（一般疑问句） __________ this a natural cave that __________ formed by natural forces? 3. The rock took shape because of wind erosion.（用may改写） The rock __________ __________ taken shape because of wind erosion. 4. We have visited the vast desert in the west.（对划线部分提问） __________ __________ you visited in the west? 5. The fish are swimming below the surface of the lake.（对划线部分提问） __________ __________ the fish swimming? 6. He has found out the secret of the natural wonder.（改为一般疑问句并作否定回答） —__________ he __________ out the secret of the natural wonder? —No, he __________. 7. This is a beautiful natural wonder. It attracts many visitors.（合并为定语从句） This is a beautiful natural wonder __________ __________ many visitors. 8. The natural wonder may be very old.（改为否定句） The natural wonder __________ __________ be very old. 四、用may/might, 动词过去分词/定语从句引导词that/which, 介词填空 1. I __________ (see) the ancient tree that has survived for more than 500 years. 2. This is a natural wonder __________ __________ (create) by powerful natural forces. 3. The mystery of the cave __________ not be solved easily; it’s too strange. 4. There is a small lake __________ the mountain; we can find many fish in it. 5. —Have you ever visited a rock __________ looks like a lion? —Yes, I have. 6. She __________ (not visit) the waterfall yet; she plans to go next weekend. 7. The natural scene __________ we saw yesterday is surrounded by mountains. 8. We need to explore the cave __________ depth to find its hidden secrets. 9. The rock __________ (may) take shape thousands of years ago. 10. They have found a rare plant __________ grows only in the desert. 参考答案 一、用所给词的适当形式填空 1. have visited 2. takes 3. Have; found 4. may 5. haven’t seen 6. has created 7. might 8. have already finished 9. explored 10. have survived 二、单项选择 1.B 2.A 3.B 4.C 5.B 6.A 7.B 8.A 9.A 10.B 三、句型转换 1. haven’t; seen 2. Is; was 3. may; have 4. What; have 5. Where; are 6. Has; found; hasn’t 7. that/which; attracts 8. may; not 四、用may/might, 动词过去分词/定语从句引导词that/which, 介词填空 1. have seen 2. that/which; was created 3. may/might 4. below 5. that/which 6. hasn’t visited 7. that/which 8. in 9. may 10. that/which 学科网（北京）股份有限公司 $