沪教版八年级下册第 3 单元基础语法汇总:
1.被动语态
(1)基本结构
1 公式: be 动词 + 过去分词 (V-ed)
2 动作的承受者作主语,执行者用by + 宾语(可省略)。 例句:The cake is eaten by the children.蛋糕被孩子们吃掉了。
(2)不同时态的被动语态
时态 被动结构 例句(附翻译)
一般现在时 am/is/are + V-ed The room is cleaned every day. (房间每天被打扫。)
一般过去时 was/were + V-ed The letter was written yesterday. (信昨天被写好了。)
一般将来时 will be + V-ed The project will be finished soon. (项目很快会被完成。)
现在进行时 am/is/are being + V-ed The car is being repaired now. (车正在被修理。)
过去进行时 was/were being + V-ed The dinner was being cooked when I arrived. (我到达时,晚餐正在被 准备。)
现在完成时 have/has been + V-ed The homework has been done. (作业已经被完成了。)
(3)被动语态的使用场合
1 强调动作的承受者(而非执行者):
例句 1 :The window was broken. 窗户被打破了。
2 不知道或无需指出动作执行者:
例句:English is spoken in many countries. 许多国家说英语。
3 客观描述事实或科学结论:
例句:The earth is surrounded by air. 地球被空气包围。
(4)特殊注意事项
1 不及物动词(vi. )无被动语态:类似动词:appear, disappear, take place 例句: The accident happened yesterday. 事故昨天发生了。
2 主动表被动的动词:
例句 1 :The book sells well. 这本书卖得很好。(书“被卖”)
例句 2 :The pen writes smoothly. 这支笔写起来很流畅。(笔“被使用”)
3 带情态动词的被动:情态动词 + be + V-ed
例句:The work must be finished today. 工作今天必须被完成。
4 双宾语的被动转换:
例句 1:He gave me a book.(主动)
例句 2:A book was given to me (by him).(被动) 例句 3 :I was given a book (by him). (被动)
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(5)常见错误提醒
① 遗漏be 动词:
× The cake eaten by him. → √ was eaten
② 混淆时态和语态:
× The movie is watch by us. → √ is watched
③ 错误使用by 短语:
× The song is liked from many people. → √ by 练习巩固:
(1)They built this bridge in 2020.
(2)The news (report) on TV yesterday.
2. 一般现在时(Simple Present Tense):用于描述习惯性动作(如 日常活动)、 普遍真理(自然规律)或当前状态。
第三人称单数(he/she/it)需加 -s/-es(例:catches, uses)
例句 1:Damin sets off in the late afternoon. 大民傍晚出发。
例句 2 :Cormorants dive underwater to catch fish. 鸬鹚潜入水中捕鱼。 例句 3:Farmers use cats to control mice. 农民用猫控制老鼠。
常见错误:忘记第三人称单数的动词变化(如“He use cormorants” → 错误)。
练习题:用动词的正确形式填空:
(1)The fisherman ______ (clean) his boat every morning.
(2)She ______ (go) to the market every day.
将以下句子改为一般现在时:
Damin is tying grass around the birds. → Damin grass around the birds.
3. 情态动词(Modal Verbs)
1 can 表示能力或可能性 例句:They can swim well.
2 must 表示义务或必要性 例句:You must listen carefully.
3 should 表示建议
例句:You should check the temperature.
4 may/might 表示可能性 例句:It may rain tomorrow.
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、例句 1:Blind people must use dogs to guide them. 盲人必须用导盲犬引路。
例句 2 :Students should finish their homework on time. 学生应按时完成作业。 例句 3 :The light might attract fish at night. 灯光可能在晚上吸引鱼。
练习题:选择正确的情态动词填空:
(1)You ______ (should/can) wear a coat; it’s cold outside.
(2)The fisherman ______ (can/must) use nets if he wants more fish.
用情态动词改写句子:
It is necessary to check the eggs. → You check the eggs.
4.动词不定式(Infinitive):to + 动词原形,表示 目的(例:to catch fish)、愿 望(例:want to learn)或未完成的动作。
常用结构:need to, want to, try to, decide to。
例句 1 :Damin ties grass to prevent the birds from eating big fish. 大民绑草是为了 防止鸟吃大鱼。
例句 2 :She wants to learn paper cutting. 她想学剪纸。
例句 3 :They need to use a light to attract fish. 他们需要灯来吸引鱼。
练习题:用动词不定式补全句子:
(1)He jumps up and down ______ (attract) fish.
(2)The children decided ______ (make) a poster.
将以下句子改为含动词不定式的结构:
Damin uses grass. The purpose is to stop the birds. → Damin uses grass .
5. 介词短语(Prepositional Phrases):介词(in, on, at, under, around)与名词/代 词搭配,表示时间、地点或方式。
常见搭配:
1 at + 具体时间/小地点(at 4 p.m., at home)
2 on + 表面/日期(on the boat, on May 4th)
3 in + 大地点/时间段(in China, in the morning)
例句 1 :The fisherman hangs a light on a post. 渔夫在柱子上挂灯。 例句 2 :The audience sits in front of the screen. 观众坐在屏幕前。 例句 3 :The fish are thrown into a basket. 鱼被扔进篮子里。
练习题:选择正确的介词填空:
(1)The boat is ______ (in/on) the river.
(2)The programme was filmed ______ (at/in) a small village.
(3)描述位置(鸟在船上):The cormorants are ______ the boat.
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6. 比较级与最高级(Comparative & Superlative):
(1)比较级:用于两者比较,结构为 形容词 + -er 或 more + 形容词。 例子:big → bigger, interesting → more interesting
(2)最高级:用于三者及以上比较,结构为 the + 形容词 + -est 或 the most + 形 容词。
例子:big → the biggest, interesting → the most interesting
不规则变化:good → better → best;bad → worse → worst
例句 1 :This basket is bigger than that one. 这个篮子比那个大。
例句 2 :Shadow puppets are the most colorful traditional art. 皮影是最多彩的传统 艺术。
例句 3:Paper cutting is not as difficult as cormorant fishing. 剪纸不如鸬鹚捕鱼难。
练习题:写出比较级和最高级:
(1)happy → ______ → ______
(2)expensive → ______ → ______
用比较级或最高级填空:
(1)Damin is ______ (old) fisherman in the village.
(2)This rope is ______ (long) than that one.
7. 连接词(Conjunctions):并列连接词(and, but, or)连接同等成分。
从属连接词(although, because, so)连接主从句,表因果、让步等关系。 例句 1:Although he is old, he works every day. 尽管他老了,仍每天工作。
例句 2:Cormorants are good at fishing because they can swim well. 鸬鹚擅长捕鱼, 因为它们游得好。
例句 3 :The film is interesting, but few people watch it. 电影有趣,但看的人少。
练习题:用 although 或 because 连接句子:
The light is bright. Fish are attracted to it. →
选择正确的连接词:
He wants to learn paper cutting, (and/but) he has no time.
8. 祈使句(Imperative Sentences):以动词原形开头,省略主语(you),用于 指令、建议或请求。
否定形式:Don’t + 动词原形。
例句 1:Look at the picture carefully. 仔细看图片。 例句 2:Don’t use nets for fishing. 不要用网捕鱼。
例句 3:Please describe the steps clearly. 请清楚地描述步骤。
练习题:将以下句子改为祈使句:
(1)You should check the temperature. →
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(2)You must not talk during the film. → ______
9. 形容词顺序(Adjective Order):多个形容词修饰名词时,顺序规则为: 观点 → 尺寸 → 年龄 → 形状 → 颜色 → 材料 → 用途
例子:a beautiful small old round red wooden box 例句 1 :She has long, black hair. 她有长长的黑发。
例句 2:He is a tall, young fisherman. 他是一个高大的年轻渔夫。
练习题:排列形容词顺序:
(1)a / leather / red / small / bag → ______
(2)an / Chinese / ancient / art → ______
10. There be 句型:表示“存在” ,结构为 There is/are + 名词 + 地点。 is 用于单数名词,are 用于复数名词。
例句 1 :There are many fish in the river. 河里有很多鱼。 例句 2 :There is a light on the boat. 船上有一盏灯。
练习题:用 There is/are 填空:
(1)______ a big net on the boat.
(2)______ many cormorants in the village.
将以下句子改为疑问句:
There are seven mistakes in the picture. →
11. 冠词(Articles):a/an:泛指单数可数名词(a 用于辅音开头,an 用于元音 开头)。
the:特指已知的人或物,或唯一的事物(如 the sun)。 例句 1:Damin is a fisherman. 大民是一个渔夫。
例句 2 :The cormorants catch fish for the boat. 鸬鹚为船捕鱼。
练习题:选择 a/an/the 填空:
(1)He uses ______ old boat.
(2)I______ audience clapped loudly.
改正句子中的冠词错误:
She is an teacher. →
答案示例:
一般现在时:1. cleans; 2. goes → Damin ties 情态动词:1. should; 2. must → must
动词不定式:1. to attract; 2. to make → to stop the birds 介词:1. on; 2. in
比较级:happier → happiest; more expensive → most expensive 连接词:Because the light is bright, fish are attracted to it.9
祈使句:Check the temperature. / Don’t talk during the film.
形容词顺序:a small red leather bag / an ancient Chinese art
There be:1. There is; 2. Are there seven mistakes in the picture 冠词:1. an; 2. The → She is a teacher.
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