Unit 4 Section A Grammar Focus 4a-4d 课件 2025-2026学年人教版英语八年级下册

SectionA(4a-4d) The Wonders of Nature Unit 4 Learning Objectives 语言能力 Identify comparatives /superlatives in reading; read/write large numbers; use regular forms to compare natural places; complete passage with correct forms. 学习能力 Summarize 5 formation rules; infer new words from context; practice comparison Q&A with partners. 文化品格 Learn global & Chinese natural wonders; appreciate nature & build environmental awareness. 思维品质 Analyze natural features with comparatives /superlatives; distinguish & apply comparatives (2 things) & superlatives (3+ things). the Yangtze River (6300km) the Yellow River (5464km) the Nile River (6670km) The Yangtze River is longer than the Yellow River. The Nile River is longer than the Yangtze River. The Nile River is the longest. the Sahara Desert (906 km²) the Taklamakan Desert (33 km²) the Arabian Desert (233 km²) The Sahara Desert is larger than the Taklamakan Desert. The Arabian Desert is larger than the Sahara Desert. The Arabian Desert is the largest. 1. Talk about geographical facts size height length depth measurement 2. Compare them with other natural wonders How can we introduce a natural wonder? What should we use to talk about the geographical facts and compare them with other natural wonders? Large numbers Positives Comparatives Superlatives Different forms of adjectives and adverbs: Grammar Large numbers Positives Comparatives Superlatives Write down the correct numbers according to the geography facts. 1. The surface of the Dead Sea is _______ metres below sea level. 2. The Yangtze River is about ______ kilometres long. 3. The Nile River is ________ kilometres long. 4. Mount Qomolangma is __________ metres high. 5. The Mariana Trench is about _________ metres deep. 6. The Sahara Desert is about ___________ square kilometres in size. 416 6,300 6,671 8,848.86 11,000 9,000,000 How can we read these numbers? Grammar Large numbers Positives Comparatives Superlatives 416 6,300 6,671 8,848.86 11,000 9,000,000 How can we read these numbers? four hundred and sixteen six thousand three hundred six thousand six hundred and seventy-one eight thousand eight hundred and forty-eight point eight six eleven thousand nine million Can you find the rules? Grammar Large numbers Positives Comparatives Superlatives How can we read large numbers? 2 506 112 375 . 53 Grammar Large numbers Positives Comparatives Superlatives How can we read large numbers? 2 506 112 375 ①先从右至左数,每三位 数加一个逗号.(先忽略 小数点及后面部分) , , , ②第一个逗号代表thousand(千), 第二个逗号代表 million(百万), 第三个逗号代表billion(十亿). thousand 千 million 百万 billion 十亿 two billion, five hundred and six million, one hundred and twelve thousand, three hundred and seventy-five, . 53 ③point+小数 点后逐个读 point 点 point five three 注意: ① 英语中没有“万”这个单位,要表示“万”须借用“千”表示(ten thousand),“十万”用“百个千”表示(one hundred thousand)。 ② hundred 后通常加连词 and。若读数中百位数为 0,则在 thousand 后加 and。 Grammar Large numbers Positives Comparatives Superlatives Let’s practice. 2,850 7,129 9,600.50 15,308 2,500,000 12,467 two thousand eight hundred and fifty seven thousand one hundred and twenty-nine nine thousand six hundred point five zero fifteen thousand three hundred and eight two million five hundred thousand twelve thousand four hundred and sixty-seven Grammar Large numbers Positives Comparatives Superlatives Write or spell out the numbers. 4b Mount Kilimanjaro is ________ (five thousand, eight hundred and ninety-five) metres high. ________ (twenty-five thousand, seven hundred and sixty-eight) cubic metres of water pours down Inga Falls each second. The East African Rift Valley is about 4,000 (___________) miles long. The Taklimakan Desert has a total area of about 337,000 (______) square kilometres. 5,895 25,768 three hundred and thirty-seven thousand four thousand / ˈkjuːbɪk/ adj.立方的 /ˌkɪlɪmənˈdʒɑːrəʊ/ 乞力马扎罗山(非洲最高峰) /rɪft / /ˈvæli/ 东非大裂谷 /ˌtækləˈmɑːˈkæn/ 塔克拉玛干 What does each number represent? Grammar Large numbers Positives Comparatives Superlatives Write or spell out the numbers. 4b Mount Kilimanjaro is ________ (five thousand, eight hundred and ninety-five) metres high. ________ (twenty-five thousand, seven hundred and sixty-eight) cubic metres of water pours down Inga Falls each second. The East African Rift Valley is about 4,000 (___________) miles long. The Taklimakan Desert has a total area of about 337,000 (______) square kilometres. 5,895 25,768 three hundred and thirty-seven thousand four thousand Height Volume Length Size Grammar Large numbers Positives Comparatives Superlatives Let’s read a passage about two amazing places. Can you guess what they are? There are two amazing places on earth. The first place is much drier than most other places. It is one of the hottest places during the daytime. The days there are usually sunnier than in most places, but the nights can be colder than you think. Plants are not as common as in other places because water is one of the most difficult things to find here. The second place is greener than almost anywhere else. The rain falls the heaviest in this place. The trees grow taller and thicker than the ones in cities. The air there is much fresher than in other places. Desert Rainforest Grammar Large numbers Positives Comparatives Superlatives Circle the adjectives which compare things. Underline the adverbs which compare actions. Desert Rainforest There are two amazing places on earth. The first place is much drier than most other places. It is one of the hottest places during the daytime. The days there are usually sunnier than in most places, but the nights can be colder than you think. Plants are not as common as in other places because water is one of the most difficult things to find here. The second place is greener than almost anywhere else. The rain falls the heaviest in this place. The trees grow taller and thicker than the ones in cities. The air there is much fresher than in other places. Tip: Adjectives modify nouns, and adverbs modify verbs. Positives Comparatives Superlatives 概述: 大多数形容词和副词有三个等级:原级(positive), 比较级(comparative)和最高级(superlative)。 Grammar Large numbers Positives Comparatives Superlatives 比较级和最高级的构成 分类 构成方式 例词 单音节词和部分双音节词 多音节词和部分双音节词 一般情况： 词尾直接加 -er / -est long → longer → longest deep → deeper → deepest 以字母 e 结尾： 直接加 -r / -st large → larger → largest wide → wider → widest 辅音字母 + y 结尾： 变 y → i，再加 -er / -est dry → drier → driest heavy → heavier → heaviest 重读闭音节 + 单个辅音结尾： 双写辅音，再加 -er / -est hot → hotter → hottest big → bigger → biggest 多音节/部分双音节词: 在词前加 more / most difficult → more difficult → most difficult amazing → more amazing → most amazing (1)规则变化 (2)不规则变化 Grammar Large numbers Positives Comparatives Superlatives 比较级和最高级的构成 (1)规则变化 (2)不规则变化 原级 比较级 最高级 good / well bad / badly many / much little (少) old far better best more most worse worst less least farther/further farthest/furthest older/elder oldest/eldest 1. tall __________ _________ 2. long __________ __________ 3. slow __________ __________ 4. large __________ __________ 5. late __________ __________ 6. big __________ __________ 7. happy __________ _______ 8. loud __________ __________ 9. easy __________ __________ 10. nice __________ __________ 11. amazing_______________ ________________ 12. quickly______________ ________________ 13. well __________ __________ 14. little __________ __________ taller tallest longer longest slower slowest larger largest later latest bigger bigger happier happiest louder loudest easier easiest nicer nicest more amazing most amazing more quickly most quickly better best less least Grammar Large numbers Positives Comparatives Superlatives 比较级和最高级的构成 (1)规则变化 (2)不规则变化 Grammar Large numbers Positives Comparatives Superlatives 原级(同级比较)用法 肯定结: A + 谓语 + as + 原级 + as + B. A 和 B 一样…… 肯定结: A + 谓语 + not as/so + 原级 + as + B. A 不如 B …… 1. 这个湖泊和这条河流一样清澈。 2. 这个湖泊不如海洋深。 The lake is as clean as the river. The lake is not as/so deep as the sea. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 1. A + 谓语动词 + 比较级 + than + B. A 比 B 更…… 1.长江比黄河长一点。 The Yangtze River is a little longer than the Yellow River. 前提：表示“两者”之间进行比较 2. 撒哈拉沙漠比塔克拉玛干沙漠更大。 The Sahara Desert is larger than the Taklimakan Desert. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 2. Which / Who + 谓语动词 + 比较级, A or B? A 和 B 中，哪一个/谁更……？ 1.珠穆朗玛峰和乞力马扎罗山，哪一座更高？ Which is higher, Qomolangma or Kilimanjaro? 前提：表示“两者”之间进行比较 2. 尼罗河和亚马逊河，哪一条更长？ Which is longer, the Nile or the Amazon? Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 3. A + 谓语动词 + the + 比较级 + of the two. 两者中，A 是更……的那一个 1.这两座沙漠中，撒哈拉沙漠是更大的那一座。 The Sahara is the larger of the two deserts. 前提：表示“两者”之间进行比较 2. 这两条河流中，尼罗河是更长的那一条。 The Nile is the longer of the two rivers. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 4. The + 比较级 + 主谓, the + 比较级 + 主谓. 越……，就越…… 1.山越高，空气就越稀薄。 The higher the mountain is, the thinner the air is. 前提：表示“两者”之间进行比较 2. 河流越长，它的流域就越宽广。 The longer the river is, the wider its basin is. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 5. 比较级 + and + 比较级 / more and more + 原级 越来越…… 1.黄河变得越来越清澈。 The Yellow River is becoming cleaner and cleaner. 前提：表示“两者”之间进行比较 2. 这些山脉变得越来越翠绿。 The mountains are getting greener and greener. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 6. 主语 + 谓语动词 + 比较级 + than any other + 单数名词 + 范围. =主语 + 谓语动词 + 比较级 + than the other + 复数名词 + 范围. …比同一范围内其他任何一个都…(比较级表最高级) 1.长江比中国其他任何河流都长。 The Yangtze is longer than any other river in China. 前提：表示“两者”之间进行比较 2. 珠穆朗玛峰比亚洲其他任何山峰都高。 Qomolangma is higher than the other mountains in Asia. Grammar Large numbers Positives Comparatives Superlatives 比较级的用法 比较级修饰词 常见的有much, a lot, a little, a bit, even, still, far等. 助记口诀: 两 “多”两 “少”一 “甚至”， “还”有一个 “远”去了。 - 两多：much, a lot - 两少：a little, a bit - 一甚至：even - 还：still - 远去了：far 1. 撒哈拉沙漠比塔克拉玛干沙漠大得多。 2. 珠穆朗玛峰峰顶甚至更冷。 3. 亚马逊河甚至比长江还要长。 The Sahara Desert is much larger than the Taklimakan Desert. It is even colder on the top of Qomolangma. The Amazon is still longer than the Yangtze. Grammar Large numbers Positives Comparatives Superlatives 最高级的用法 1. 主语 + 谓语动词 + (the) + 最高级 + 范围. ……在某范围内最…… 1.亚马逊河在南美洲流程最远。 The Amazon River travels (the) farthest in South America. 前提：表示“三者或三者以上”之间进行比较 2. 里海是世界上最大的湖泊。 The Caspian Sea is the largest lake in the world. Grammar Large numbers Positives Comparatives Superlatives 最高级的用法 2. 主语 + 谓语动词 + one of the + adj.最高级 + 复数名词 + 范围. …是最…之一 1.维多利亚瀑布是世界上最美的瀑布之一。 Victoria Falls is one of the most beautiful waterfalls in the world. 前提：表示“三者或三者以上”之间进行比较 2. 科罗拉多大峡谷是世界上最壮观的自然奇观之一。 The Great Canyon is one of the most wonderful natural wonders in the world. Grammar Large numbers Positives Comparatives Superlatives 最高级的用法 3. 主语 + 谓语动词 + the + 序数词 + adj.最高级 + 名词 + 范围. …是第几最…的 前提：表示“三者或三者以上”之间进行比较 1.长江是世界上第三长的河流。 The Yangtze is the third longest river in the world. 2. 黄河是中国第二长的河流。 The Yellow River is the second longest river in China. Grammar Large numbers Positives Comparatives Superlatives 最高级的用法 4. Which + 谓语动词 + (the) + 最高级, A, B or C? A、B、C 中，哪一个最……？ 前提：表示“三者或三者以上”之间进行比较 1.尼罗河、长江、亚马逊河，哪一条最长？ Which is the longest, the Nile, the Yangtze or the Amazon? 2. 珠穆朗玛峰、乞力马扎罗山、勃朗峰，哪一座最高？ Which is the highest, Qomolangma, Kilimanjaro or Mont Blanc? Grammar Large numbers Positives Comparatives Superlatives 最高级的用法 最高级前不用/可省 the 的情况 1. 最高级前有名词所有格/物主代词修饰时，不加 the; 1. 中国最长的河流是长江。 2. 这片沙漠是亚洲最大的。 3. 山顶上的风刮得最猛。 China’s longest river is the Yangtze. This desert is (the) largest in Asia. The wind blows (the) strongest on the mountain top. 2. 形容词最高级作表语时，the 可省 3. 副词最高级前 the 可加可省 Grammar Large numbers Positives Comparatives Superlatives 最高级与比较级之间的转换 拓展: 形容词与副词的最高级可与 “比较级 + than any other + 单数名词” 或 “比较级 + than the other + 复数名词”进行相互转换. 1.长江比中国其他任何河流都长。 The Yangtze is longer than any other river in China. 2. 珠穆朗玛峰比亚洲其他任何山峰都高。 Qomolangma is higher than the other mountains in Asia. =The Yangtze is the longest river in China. =Qomolangma is the highest mountain in Asia. Summary Large numbers Positives Comparatives 1. 从右至左每三位分一节，依次为thousand（千）、million（百万）、billion（十亿）；无“万”，用ten thousand表示，“十万”用one hundred thousand表示。 2. 百位和十位间加and（英式），百位数为0时，在thousand后加and。 3. 小数点读point，小数点后数字逐个读。 肯定结构: A + 谓语 + as + 原级 + as + B （A和B一样……） 否定结构: A + 谓语 + not as/so + 原级 + as + B （A不如B……） 1. A + 谓语 + 比较级 + than + B （A比B更……） 2. Which/Who + 谓语 + 比较级, A or B? （A和B中，哪一个/谁更……？） 3. A + 谓语 + the + 比较级 + of the two （两者中，A是更……的那一个） 4. The + 比较级 + 主谓, the + 比较级 + 主谓 （越……，就越……） 5. 比较级 + and + 比较级 / more and more + 原级 （越来越……） 6. 主语 + 谓语 + 比较级 + than any other + 单数名词 + 范围 = 主语 + 谓语 + 比较级 + than the other + 复数名词 + 范围 （……比同一范围内其他任何一个都……，表最高级） Summary Superlatives 1. 主语 + 谓语 + (the) + 最高级 + 范围 （……在某范围内最……） 2. 主语 + 谓语 + one of the + 形容词最高级 + 复数名词 + 范围 （……是……中最……之一） 3. 主语 + 谓语 + the + 序数词 + 形容词最高级 + 名词 + 范围 （……是……中第几最……的） 4. Which + 谓语 + (the) + 最高级, A, B or C? （A、B、C中，哪一个最……？） 同义转换 比较级 + than any other + 单数名词 + 范围 比较级 + than the other + 复数名词 + 范围 = the + 最高级 + 范围 Practice makes perfect. 34 Victoria Falls My friends and I visited Victoria Falls in Africa last year. Visiting one of the world’s ______________ waterfalls was a magical experience. As we went __________ to the falls, the noise of the water slowly grew __________ and louder. Then, right before our eyes, the waterfall appeared. It went on for as ___________ as the eye could see. Later, we sat in a special pool at the top of the falls. There, we felt the water rush past us and become a part of the waterfall. It was the scariest but also the ________________ experience of our trip! 4c Complete the passage with the correct forms of the words in the box. largest large　 amazing 　far　 close 　loud closer louder far most amazing one of the + 最高级+cn复数 went closer 走近 比较级+and+比较级 as +原级+as the+最高级+范围 How does the writer make the description vivid? Tip: Find the answer by looking for “sensory words” — words that tell us what we see, hear, and feel. My friends and I visited Victoria Falls in Africa last year. Visiting one of the world’s ______________ waterfalls was a magical experience. As we went __________ to the falls, the noise of the water slowly grew __________ and louder. Then, right before our eyes, the waterfall appeared. It went on for as ___________ as the eye could see. Later, we sat in a special pool at the top of the falls. There, we felt the water rush past us and become a part of the waterfall. It was the scariest but also the ________________ experience of our trip! 4c Complete the passage with the correct forms of the words in the box. largest large　 amazing 　far　 close 　loud closer louder far most amazing Hearing(听觉) Sight(视觉) 它延伸得很远,一眼望不到边. Touch(触觉) Personal experiences and feelings can be added to introduce natural wonders 4d Write some questions to compare places. Then ask a partner your questions. What is the highest ...? Which park is bigger, ... or ...? What is the deepest ...? What is the most famous ...? Which ... is longer, ... or ...? Which ... is higher, ... or ...? Is ... as deep as ...? Is ... as amazing as ...? 温馨提示:这个活动和后面的推荐官选其一即可哦 $