★2018仁爱版八年级下册知识点讲解(一)

仁爱版八年级下册知识点讲解（一）2018.4.15.应掌握的语法知识(一)：

时间状语从句和条件状语从句中，将来动作要用一般现在时表示(不能用将来时)，但主句时态该用什么时态就用什么时态。

1. 以when，before，after，as soon as，until/till，while，as等引导的是时间状语从句;

2.以if，unless等引导的是条件状语从句。

例如：

I'll tell her the good news when she comes back.当她回来的时候，我将把这个好消息告诉她。(不能说：...she will come...)

If it doesn't rain, he will come here on time.如果不下雨，他会按时来这儿的。(不能说：If It will not rain，...)

3.以下三种情况通常表明从句是将来动作：

一、主句是一般将来时：如：

When I grow up, I’ll be a nurse and look after patients. 我长大后要当一名护士，照顾病人。 (不能说：When I will grow up,...)

二、主句是祈使句：如：

Don’t laugh at me when I make a mistake. (不能说：...when I will make ...)

我犯错误的时候不要笑话我。

三、主句含有情态动词：如：

You should be quiet when you are in the reading room. (不能

说：...when you will be in the ...)

在阅览室时应保持安静。

应掌握的语法知识(二)：

when, while, as的用法区别：

1、When“当...时”可指时间点,又可指时间段,从句中可用延续性动词(长),也可用非延续性动词(短).

When I arrived home,she was cooking.我到家时她正在做饭。

When she was cooking,I arrived home.她正在做饭时我到家了。

She left when I arrived home.我到家时她走了。

She finished her homework when she was at school.她在学校时就把作业做完了。

2、While“在...期间”总是指一个时间段,从句中必须用延续性动词(长).

While Jack was playing basketball,I was drawing pictures.杰克打篮球时我在画画。

While Jack was playing basketball,Maria arrived.杰克正在打篮球时玛丽亚到了。While we were in Xi'an,we visited some places of interest.我们在西安期间去参观

了一些名胜古迹。

3、as“一边...，一边...”，“随着...”多用于平行结构.表示两个动作同时发生：一个主语同时进行两个动作：一种状态随另一种状态的变化而变化.

Tom sang songs as he walked.汤姆一边走路一边唱歌。

The students took notes as they listened.学生们一边听课一边做笔记。

As it grew darker it became colder.随着天渐渐变黑，天气也渐渐变冷。

4、表示主句的动作发生在从句的较长动作过程中,when,while,as均可使用.从句中为be动词时,多用when和while.谈论两个同时进行的长动作可用while；谈论两个平行动作或两种状态变化多用as.

5、短动词常用一般过去时/一般现在时，长动词常用过去进行时/现在进行时。应掌握的语法知识(三)：

一、spend的主语必须是人，表示‘花费时间或金钱’ ，有以下结构：

(1)sb. spend time ／money on sth. 某人在……上花费时间[/钱]。

(2)sb. spend time ／money (in) doing sth. 某人花费时间[/钱]做某事。

例①I spent two hours on this maths problem. 这道数学题花了我两个小时。

例② They spent two years (in) building this bridge. 造这座桥花了他们两年时间。

二、take 表示‘花费时间’，主语是it，句型为：

It takes sb. ＋时间＋to do sth. 做某事花了某人多少时间。

例：It took them three years to build this road. 他们用了三年时间修完了这条路。

三、cost通常表示‘花费金钱’ ，主语通常是‘物’或it，句型为：

①sth costs（sb）money 某物花某人多少钱

②it costs（sb）money to do sth 做某事花某人多少钱

③sth costs money 某物值多少钱（这句型costs通常用一般现在时）

例①This skirt cost her 100 yuan. 这条裙子她花100元买的。（这里的cost是过去式）

=She spent 100 yuan on this skirt. =She spent 100 yuan (in) buying this skirt.

=She paid 100 yuan for this skirt.

例②It cost him one million yuan to build his house. 他建房子花了100万元。

=He spent one million yuan (in) building his house.

=He spent one million yuan on his house.

例③ This car costs 500000 yuan. 这辆车值50万元。（这句型costs通常用一

般现在时）

四、pay‘付款’ 的基本句型是：pay (sb.) money for sth{.买……付给某人多少钱例：I paid them 20 pounds for this shirt.我买这件衬衫付给他们20英磅。

五、buy '买' 的句型：sb.buy sth. for money.某人买某物花了多少钱例如：She bought the dress for 800 yuan. 她买那件连衣裙花了800块钱。=She paid 800 yuan for the dress . =She spent 800 yuan on the dress . =She spent 800 yuan (in) buying the dress . =The dress cost her 800 yuan

应掌握的语法知识(四)：

too, also, as well, either的区别

一、too,also,as well 用于肯定句；either用于否定句。

He went there, too.

＝He also went there.

＝He went there as well.

＝He,too，went there.

他也去了那里。

He didn't go there ,either.

他也没去那里。

二、too,either和as well放在句末,而also放在句中(be动词/情态动词/助动词之后,行为动词之前);too也可以放在句中，但必须在too的前、后都加上逗号。如：

He went there, too.＝He,too，went there.

My father is a teacher.My mother is also a teacher.

=My father is a teacher.My mother is a teacher as well.

=My father is a teacher.My mother is a teacher,too.

我爸爸是一名老师,我妈妈也是.

I can’t speak French.Jenny can’t speak French,either.

我不会说法语,詹妮也不会.

(补充：如果as well as用作连词引出比较从句,其义为“和…一样好”.因此,“He speaks Spanish as well as English．”应译作：“他说西班牙语像说英语一样好”.语意的重点依旧在前部,不在后半部.

请注意：as well as (除……外，……也) 以下的用法：

She called on you as well as I.

不但我来看你,她也拜访了你.

She called on you as well as me．

她不但拜访了我,也拜访了你.

在下列句中,as well as表示“像…一样”的涵义：

She as well as you is an English teacher．

她像你一样也是英文教师.)

应掌握的语法知识(五)：

used to do和be/get used to doing的用法区别

①be used to doing习惯于做某事,be可以用作各种时态.be 可以用get或become等连系动词替换。to是介词，后需加名词或动名词(doing)

②used to do过去常常（现在不做了）,只限于过去的含义.

例如：

1)I am used to going to school by bike now.我现在习惯于骑自行车去上学。

2)Mike used to eat with knife and fork,but now he is used to eating with chopsticks.

麦克过去用刀叉吃饭，现在习惯于用筷子了。

3)I used to smoke。我以前抽烟(现在不抽)。

4)I am used to getting up early.我(现在)习惯于早起。

5)I used to play basketball after school, but now I don't.

我过去放学后经常去打篮球，但现在不打了。

应掌握的语法知识(六)：

fail的用法

( fail to do sth 表示没能做成没事，或者fail in (doing) sth 表示做什么事失败了)

fail后面接动词+ing

1. 表示“失败”，通常是不及物动词。表示在某一方面失败，通常用介词in。如：He failed in business. 他经商失败。

He failed in everything he tried. 他想的一切办法都没成功。

2. 表示“(考试)不及格”，fail 可用作及物或不及物动词(以及物动词为多见)，所以以下各例中fail 后的介词in 均可以省略：

He failed (in) his driving-test. 他驾驶考试没及格

She failed (in) her exams again. 她考试又没有及格。

3. 其后可接不定式，意为“不能”“没有”“忘记”等。如：

He failed to pass the exam. 他考试没有及格。

He failed to get there on time. 他未能准时赶到那儿。

4. 表示“不能成功地做某事”，有时可后接in doing sth。比较:

他未能说服她。

正：He failed to persuade her.

正：He failed in persuading her.