作业帮初三英语重要知识点有哪些?
来源：学生作业帮 编辑：作业帮 分类：英语作业 时间：2024/04/24 18:37:21
初三英语重要知识点有哪些?
动词不定式一. 定义：
动词不定式是非谓语动词的一种,它没有人称和数的变化,在句子中不能独立作谓语,但它仍保持动词的特点,既可以有自己的宾语和状语.同时动词不定式又具有名词、形容词、副词的特征,在句中可以作主语、表语、宾语、宾语补足语、定语和状语
二. 动词不定式的构成：to+动词原形
三. 动词不定式作宾语后面能接不定式作宾语的动词有：agree, ask, choose, decide, forget, hope, learn, want, wish, would like等.
We hope to get there before dark. The girl decided to do it herself.
动词不定式作宾语的注意事项（2点）
1. 有些动词既可跟不定式作宾语,也可跟动名词作宾语,但含义不同：
remember to do 记住要做某事 remember doing 记得曾经做过某事
forget to do忘记要做某事 forget doing 忘记曾经做过某事
stop to do 停下来去做某事 stop doing 停止做某事
go on to do 继续做另一件事 go on doing 继续做原来在做的事
I remember seeing you somewhere before
Please remember to turn off the light when you leave.
2. 不定式作宾语时,如带有宾语补足语,则要把不定式放到后面,用it作形式宾语,构成“主语+动词+it+宾补（形容词、名词）+不定式”结构.
如：He found it very difficult to get to sleep.
四. 动词不定式作宾语补足语 1. 后面能接to不定式作宾语补足语的动词有：ask, order, teach, tell, want, wish, help等.
The teacher told us to do Exercise 1.
I want both of you to go. We helped her (to) repair her bike.
2. 使役动词let, have, make及感官动词see, watch, notice, hear, feel等要以不带to的不定式作宾补.
Let’s have a rest. I saw him come in.
感官动词后既可跟不带to的不定式作宾补,也可跟v-ing作宾补,前者表示动作的全部过程已结束；后者表示动作正在进行.
I saw him come downstairs.我看见他下了楼.（说明他下楼了这件事）
I saw him coming downstairs.我看见他在下楼.（说明他下楼时的情景）
五. 动词不定式作状语
Later he left home to work in different cities.
He went to see a football match.
In order to catch the other students, I must work hard.
六. 动词不定式作定语一般放在所修饰的词的后面.
I need something to eat. Do you have something to read?
Tom was so excited that he had no word to say.
He is really a fool only to eat.
The man to stand here just now is our English teacher.
The doctor had no way to save the patient.
注意：（1）作定语的不定式是由及物动词组成,被修饰的名词或代词与不定式之间存在方位或方式关系需要有介词.
I am looking for a room to live in（方位关系）
We have many things to do experiments with. （方式关系）
（2）作定语的不定式是由“be + adj + prep”构成的动词短语.
Here there isn’t any book for me to be interested in.
We have done many things to proud of.
七. 动词不定式作主语To give is better than to receive.
To reach there on foot is impossible.
动词不定式作主语时,可以用it 代替,把实际主语不定式放在后面.
It’s better to give than to receive.
It’s impossible to reach there on foot.
It’s + adj + for sb. to do sth.
It’s not difficult for me to study English well.
It’s easy for him to work out this math problem.
在这个句型中,如果形容词与不定式的逻辑主语关系密切,并且形容词用来说明逻辑主语性质、品质、特点等,由of引出逻辑主语.这类形容词主要有nice, kind, good, wrong, right等.
八. 动词不定式和疑问词连用
动词不定式可以和疑问词what, which, how, where, when连用,构成不定式短语,可以作主语、宾语、表语、宾语补足语等.
How to do is still a question. Have you decided when to leave?
九. 动词不定式的否定形式
动词不定式的否定式是在to前加not；不带to的不定式则在动词前加not. 如：
Zhang Ming asked me not to stay at home all day.
My mother let me not do it by myself.
被动语态两种语态：主动语态和被动语态
主动语态（The Active Voice）表示主语是动作的执行者.
被动语态（The Passive Voice）表示主语是动作的承受者.
构成：承受者+助动词be+及物动词的过去分词+by+执行者
一般现在时：承受者+助动词am / is/are +及物动词的过去分词+by+执行者
一般过去时：承受者+助动词was / were +及物动词的过去分词+by+执行者
承受者+助动词shall / will be+及物动词的过去分词+by+执行者
承受者+助动词 have/ has been+及物动词的过去分词+by+执行者
承受者+ can /may/must/should +be+及物动词的过去分词+by+执行者
被动语态用法：
1）当我们不知道动作的执行者是谁,或者没有必要指出动作的执行者时,需用被动语态.
2）当我们需要强调动作的承受者时,常用被动语态.
3）如果需要说出动作的执行者, 用by引导出动作的执行者.
主动语态变为被动语态时,其谓语动词的时态要与原句时态保持一致,其谓语动词的数要与新主语保持一致.
主动语态变为被动语态时有以下几种情况：
1）主语＋谓语动词＋宾语 将主动语态的宾语变为被动语态的主语.
（主动）We bought a book yesterday.
（被动）The book was bought yesterday.
2）主语＋谓语动词＋间接宾语＋直接宾语
将主动语态中一个宾语变为被动语态的主语.多数情况下将间接宾语变为主语.如果直接宾语变为主语时,间接宾语前要加介词to / for.
（主动）He showed me a book yesterday.
（被动）I was showed a book yesterday.
（被动）The book was showed to me yesterday.
3）主语＋谓语动词＋复合宾语
含有一个由宾语加宾语补足语构成的复合宾语,变为被动语态时,将主动语态的宾语变为被动语态的主语,宾语补足语保留不变,成为主语补足语.
（主动）I found him a good pupil. （宾语补足语）
（被动）He was found a good pupil. （主语补足语）
4）短语动词变为被动语态
有些短语动词相当于一个及物动词,其后可以接宾语,因此它们也有被动语态,但短语动词是不可分割的整体,变为被动语态时不可去掉其后面的介词或副词.
（主动）We should look after the patients very well.
（被动）The patients should be looked after very well by us.
5）宾语从句变为被动语态
若主动语态中是宾语从句,变为被动语态时常用it作形式主语,而把真正的主语放在后面. It’s said that he passed the exam.
被动语态应注意的几个特殊问题：
（1）不及物动词带介词和介词宾语,在变为被动语态时,仍然要带上介词.
（主动）The students in class listen to the teacher carefully.
（被动）The teacher is listened to carefully by the students in class.（2）当动词带有复合宾语时,并且宾补是省去“to”的动词不定式时,在被动语态中应加上“to”.
（主动）They make do all the work.
（被动）We were made to do all the work.
（主动）We often hear her sing English songs.
（被动）She is often heard to sing English songs.
（主动）I see him walk to school.
（被动）He is seen to walk to school.
望采纳
动词不定式是非谓语动词的一种,它没有人称和数的变化,在句子中不能独立作谓语,但它仍保持动词的特点,既可以有自己的宾语和状语.同时动词不定式又具有名词、形容词、副词的特征,在句中可以作主语、表语、宾语、宾语补足语、定语和状语
二. 动词不定式的构成：to+动词原形
三. 动词不定式作宾语后面能接不定式作宾语的动词有：agree, ask, choose, decide, forget, hope, learn, want, wish, would like等.
We hope to get there before dark. The girl decided to do it herself.
动词不定式作宾语的注意事项（2点）
1. 有些动词既可跟不定式作宾语,也可跟动名词作宾语,但含义不同：
remember to do 记住要做某事 remember doing 记得曾经做过某事
forget to do忘记要做某事 forget doing 忘记曾经做过某事
stop to do 停下来去做某事 stop doing 停止做某事
go on to do 继续做另一件事 go on doing 继续做原来在做的事
I remember seeing you somewhere before
Please remember to turn off the light when you leave.
2. 不定式作宾语时,如带有宾语补足语,则要把不定式放到后面,用it作形式宾语,构成“主语+动词+it+宾补（形容词、名词）+不定式”结构.
如：He found it very difficult to get to sleep.
四. 动词不定式作宾语补足语 1. 后面能接to不定式作宾语补足语的动词有：ask, order, teach, tell, want, wish, help等.
The teacher told us to do Exercise 1.
I want both of you to go. We helped her (to) repair her bike.
2. 使役动词let, have, make及感官动词see, watch, notice, hear, feel等要以不带to的不定式作宾补.
Let’s have a rest. I saw him come in.
感官动词后既可跟不带to的不定式作宾补,也可跟v-ing作宾补,前者表示动作的全部过程已结束；后者表示动作正在进行.
I saw him come downstairs.我看见他下了楼.（说明他下楼了这件事）
I saw him coming downstairs.我看见他在下楼.（说明他下楼时的情景）
五. 动词不定式作状语
Later he left home to work in different cities.
He went to see a football match.
In order to catch the other students, I must work hard.
六. 动词不定式作定语一般放在所修饰的词的后面.
I need something to eat. Do you have something to read?
Tom was so excited that he had no word to say.
He is really a fool only to eat.
The man to stand here just now is our English teacher.
The doctor had no way to save the patient.
注意：（1）作定语的不定式是由及物动词组成,被修饰的名词或代词与不定式之间存在方位或方式关系需要有介词.
I am looking for a room to live in（方位关系）
We have many things to do experiments with. （方式关系）
（2）作定语的不定式是由“be + adj + prep”构成的动词短语.
Here there isn’t any book for me to be interested in.
We have done many things to proud of.
七. 动词不定式作主语To give is better than to receive.
To reach there on foot is impossible.
动词不定式作主语时,可以用it 代替,把实际主语不定式放在后面.
It’s better to give than to receive.
It’s impossible to reach there on foot.
It’s + adj + for sb. to do sth.
It’s not difficult for me to study English well.
It’s easy for him to work out this math problem.
在这个句型中,如果形容词与不定式的逻辑主语关系密切,并且形容词用来说明逻辑主语性质、品质、特点等,由of引出逻辑主语.这类形容词主要有nice, kind, good, wrong, right等.
八. 动词不定式和疑问词连用
动词不定式可以和疑问词what, which, how, where, when连用,构成不定式短语,可以作主语、宾语、表语、宾语补足语等.
How to do is still a question. Have you decided when to leave?
九. 动词不定式的否定形式
动词不定式的否定式是在to前加not；不带to的不定式则在动词前加not. 如：
Zhang Ming asked me not to stay at home all day.
My mother let me not do it by myself.
被动语态两种语态：主动语态和被动语态
主动语态（The Active Voice）表示主语是动作的执行者.
被动语态（The Passive Voice）表示主语是动作的承受者.
构成：承受者+助动词be+及物动词的过去分词+by+执行者
一般现在时：承受者+助动词am / is/are +及物动词的过去分词+by+执行者
一般过去时：承受者+助动词was / were +及物动词的过去分词+by+执行者
承受者+助动词shall / will be+及物动词的过去分词+by+执行者
承受者+助动词 have/ has been+及物动词的过去分词+by+执行者
承受者+ can /may/must/should +be+及物动词的过去分词+by+执行者
被动语态用法：
1）当我们不知道动作的执行者是谁,或者没有必要指出动作的执行者时,需用被动语态.
2）当我们需要强调动作的承受者时,常用被动语态.
3）如果需要说出动作的执行者, 用by引导出动作的执行者.
主动语态变为被动语态时,其谓语动词的时态要与原句时态保持一致,其谓语动词的数要与新主语保持一致.
主动语态变为被动语态时有以下几种情况：
1）主语＋谓语动词＋宾语 将主动语态的宾语变为被动语态的主语.
（主动）We bought a book yesterday.
（被动）The book was bought yesterday.
2）主语＋谓语动词＋间接宾语＋直接宾语
将主动语态中一个宾语变为被动语态的主语.多数情况下将间接宾语变为主语.如果直接宾语变为主语时,间接宾语前要加介词to / for.
（主动）He showed me a book yesterday.
（被动）I was showed a book yesterday.
（被动）The book was showed to me yesterday.
3）主语＋谓语动词＋复合宾语
含有一个由宾语加宾语补足语构成的复合宾语,变为被动语态时,将主动语态的宾语变为被动语态的主语,宾语补足语保留不变,成为主语补足语.
（主动）I found him a good pupil. （宾语补足语）
（被动）He was found a good pupil. （主语补足语）
4）短语动词变为被动语态
有些短语动词相当于一个及物动词,其后可以接宾语,因此它们也有被动语态,但短语动词是不可分割的整体,变为被动语态时不可去掉其后面的介词或副词.
（主动）We should look after the patients very well.
（被动）The patients should be looked after very well by us.
5）宾语从句变为被动语态
若主动语态中是宾语从句,变为被动语态时常用it作形式主语,而把真正的主语放在后面. It’s said that he passed the exam.
被动语态应注意的几个特殊问题：
（1）不及物动词带介词和介词宾语,在变为被动语态时,仍然要带上介词.
（主动）The students in class listen to the teacher carefully.
（被动）The teacher is listened to carefully by the students in class.（2）当动词带有复合宾语时,并且宾补是省去“to”的动词不定式时,在被动语态中应加上“to”.
（主动）They make do all the work.
（被动）We were made to do all the work.
（主动）We often hear her sing English songs.
（被动）She is often heard to sing English songs.
（主动）I see him walk to school.
（被动）He is seen to walk to school.
望采纳