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

Unit 4 The Wonders of Nature Lesson 4 （Section A 4a–4c） 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 We use large numbers to talk about geographical facts size height length depth measurement length Review How can we read large numbers? 3 506 112 375 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 three 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 and and and ④hundred 后通常加连词 and。若读数中百位数为 0,则在 thousand 后加 and。 Write or spell out the numbers. 4b 1. Mount Kilimanjaro is________ (five thousand, eight hundred and ninety-five) metres high. 2. __________ (twenty-five thousand, seven hundred and sixty- eight) cubic metres of water pours down Inga Falls each second. 3. The East African Rift Valley is about 4,000 (_______________) miles long. 4. The Taklimakan Desert has a total area of about 337,000 (_____________________________________) square kilometres. 5, 895 three hundred and thirty-seven thousand 25, 768 four thousand 乞力马扎罗山 立方米 pour down 倾泻而下 英加瀑布 东非大裂谷 has a total area of... 总面积为…… Practice 4 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 Observe and say hundred/thousand/million/billion 用法： Let’s learn • 2.有具体数字：基数词+hundred/thousand/million/billion • 1.表模糊概数：用复数，加s + of five hundred（500） two million（200万） hundreds of（成百上千） thousands of（成千上万） Read the sentences. Circle the adjectives which compare things. Underline the adverbs which compare actions. 4a What is the biggest desert in the world？ It is the Sahara Desert. How big is it？ It is about 9,000,000 square kilometres in size. Where is the deepest point in the ocean？ It is in the Mariana Trench. How deep is it？ It is about 11,000 metres deep. Some deep-sea animals are blind, but they can “see” as well as others. Mount Qomolangma is one of the greatest wonders of the world, and it is still growing taller. The Yangtze River travels the farthest in China and is about 6,300 kilometres long. 形容词最高级 形容词比较级 副词原级 副词最高级 比较级和最高级概念：用来修饰名词的形容词或者修饰动词的副词，会因为修饰程度不同而有所“比较”，可分为原级，比较级（更......）与最高级（最......）。 7 一、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 Review (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 Review 一、比较级和最高级的构成 1.big __________ _________ 2. high __________ __________ 3. low __________ __________ 4. deep __________ __________ 5. easy __________ __________ 6. far __________ __________ 7. happy __________ _______ 8. loud __________ __________ 9. great __________ __________ 10. close __________ __________ 11. amazing_______________ ________________ 12. interesting______________ ________________ 13. well __________ __________ 14. little __________ __________ 写出下列单词的比较级和最高级 bigger biggest higher highest lower lowest deeper deepest easier easiest farther farthest happier happiest louder loudest greater greatest closer closest more amazing most amazing more interesting most interesting better best less least Practice 二、原级(同级比较)用法 1.肯定结构: A + 谓语 + as + 原级 + as + B. A 和 B 一样…… 2.否定结构: 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干净。 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. Review 三、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……？ e.g.尼罗河和亚马逊河，哪一条更长？ Which is longer, the Nile or the Amazon? Review 1. A + 谓语动词 + 比较级 + than + B. A 比 B 更…… e.g.长江比黄河长一点。 The Yangtze River is a little longer than the Yellow River. 3. A + 谓语动词 + the + 比较级 + of the two. 两者中，A 是更……的那一个 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. 4. The + 比较级 + 主谓, the + 比较级 + 主谓. 越……，就越…… 1.山越高，温度就越低。 The higher the mountain is, the lower the temperature is. 5. 比较级 + and + 比较级 / more and more + 原级 越来越…… 长江变得越来越清澈。 The The Yangtze River is becoming cleaner and cleaner. 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) e.g.长江比中国其他任何河流都长。 The Yangtze is longer than any other river in China. 注意：比较级修饰词常见的有：much, a lot, a little, a bit, even, still, far等. 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. 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. 四、最高级的用法 1. 主语 + 谓语动词 + (the) + 最高级 + in/of/among短语 . ……在某范围内最…… 里海（Caspian Sea）是世界上最大的湖泊。 The Caspian Sea is the largest lake in the world. Review 2. 主语 + 谓语动词 + one of the + adj.最高级 + 复数名词 + 范围. …是最…之一 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. 3. 主语 + 谓语动词 + the + 序数词 + adj.最高级 + 名词 + 范围. …是第几最…的 长江是世界上第三长的河流。 The Yangtze is the third longest river in the world. 4. Which + 谓语动词 + (the) + 最高级, A, B or C? 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? 注意：最高级前有名词所有格/物主代词修饰时，不加 the; Complete the passage with the correct forms of the words in the box. 4c large amazing far close loud 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 louder and _________. 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! largest closer louder far most amazing 维多利亚瀑布 go close to 靠近;接近 就在眼前；眼皮底下 as far as the eye can/could see 望不到边，一望无垠，极目所尽 at the top of 在...的顶部 它延伸得很远,一眼望不到边. Practice 18 $