第3讲 教材梳理（语法篇2）-2023年江苏省中考英语考前必看必练10讲

这是一份第3讲 教材梳理（语法篇2）-2023年江苏省中考英语考前必看必练10讲，共16页。试卷主要包含了现在完成时，疑问词+动词不定式，enugh t d...和句式，被动语态特殊考点，过去进行时，动词不定式用法，祈使句，形容词和副词的比较级和最高级等内容，欢迎下载使用。
第3讲 教材梳理（语法篇2）-2023年江苏省中考英语考前必看必练10讲




一、现在完成时
含义：
（1）现在完成时表示过去已经开始，持续到现在,也许还会持续下去的动作或状态。可以和表示延续的时间状语连用。 如for、since 等引导的时间状语。（注意：句中谓语动词要用延续性动词）时间状语的表达方法有两种:
for: + 一段时间 for a year, for two weeks, for three years...
过去的某一时刻, since last week, since 2008…
Since 一段时间+ago, since 9 years ago, since 3 days ago…,
+点时间 一般过去时态的时间状语从句：since you came，
since he moved here, since I was born…
例如：1.Eddie has lived with Millie for 4 years.
2 since2011.
Coffey has lived in Kunshan since 4 years ago.
since she left school.
（2）现在完成时表示过去发生或已经完成的某一动作对现在造成的影响或结果。(汉语中常用“已经”、“过”、“了”等表达) 通常与表示包括现在在内的时间副词just(句中）, already(句中，句末）, before(句末）, yet（句末）, never（句中）, ever（句中）,recently(句末)等状语连用。例如：
例如：1.Eddie has just eaten my food. （Eddie已经吃了我的食物。）
2.I have never heard of that before.（我以前从未听说过那件事）
3. Have you ever ridden a horse? （你曾经骑过马吗？）
4. She has already finished the work.（她早已经完成这个工作了。）
5. We haven’t finished our homework yet. （我们还没有完成作业呢。）

现在完成时标志词
(1)表示发生在过去的或已经完成得对现在仍有影响的动作
e.g.I have lost my key.我把钥匙丢了。（过去丢的，现在还没有找到）
I have already seen the film.我已经看过那部电影了。
---Have you found your lost key yet? 你已经找到了你的钥匙了吗？
---No, I haven’t found it yet.不，我还没有找到。
批注：already, yet常和现在完成时连用。Already用于肯定句中，可放在助动词之后，过去分词之前，也可放在句末。Yet用在疑问句中意为“已经”，用在否定句中表示“还”，常放在句末。
(2)表示动作或状态在过去已经开始，并持续到现在，也许还要持续下去，常和for, since,连用。表示持续的动作或状态多用延续性动词。
e.g.Mr. Zhang has taught English for 20 years.张老师已经教了20年英语了。
(3)几个副词在现在完成时中的用法
①just意为“刚刚”，表示动作刚刚结束，常放在助动词与过去分词之间；
e.g.He has just come back from America
②ever意为“曾经”，用于疑问句或否定句中，放在助动词和过去分词之间；
e.g.Have you ever been to London? 你去过伦敦吗？
批注：重点考点have been in+地点+时间段,表示“在/来某地多久”；have gone to+地点,表示“去了某地”。（人已走，尚未回。只用于第三人称。）have been to+地点,表示“去过某地”。（人已回）。务必熟记它们的意思。
③never意为“从来没有”，常与before连用，多放在助动词与过去分词之间。
④before意为“以前”，指过去不确定的某个时候，总是放在句末，不受句型的限制。
e.g.I have never heard of this singer before. 我以前从未听说过这名歌星。
⑤since+时间点，for+时间段。
批注：总结现在完成时的时间状语ever、never、yet、already 、recently 、just、since 、for、so far、/during / in the past / last few days / weeks / months / years等。

延续性动词和终止性动词的用法
①现在完成时表示动作从过去某个时候开始一直持续到现在，而与一段时间连用时应注意句中的谓语动词必须是延续性动词，非延续性动词不能和一段时间连用。
我离开家乡已有10年了。
误：I have left my hometown for 10 years.
正：I have been away from my hometown for 10 years.
②在否定句中，终止性动词可与一段时间连用。
③终止性动词与一段时间状语连用时可采用下列三种方法：
a.将终止性动词转化为延续性动词：come—be here；go—be there; die--be dead; borrow--keep; buy--have; join--be in(be a member);leave--be away等。
b.将时间状语改为过去时间，而用一般过去时代替现在完成时。
c.用句型“it is+一段时间+since从句（从句的用一般过去时）”表示。
终止性动词
延续性动词
buy
have
borrow
keep
open
be open
close
be closed
begin/start
be on
come
be here
go
be there
finish
be over
die
be dead
catch a cold
have a cold
put on
wear
get up
be up
wake up
be awake
fall asleep
be asleep
lose
not have
join
be in
leave
be away
arrive/reach
be

现在完成时VS一般过去时
(1)一般过去时表示过去某个时间发生的事、存在的状态或经常发生的动作。
说话的侧重点只在于陈述一件过去的事情，不强调对“现在”产生的影响。
He visited Guilin in 1998.他1998年参观过桂林。（只说明去桂林的时间）
(2)现在完成时表示动作发生在过去，对现在造成了影响或产生了结果，不与确定的过去的时间状语连用。
Jill has bought a new computer.吉尔买了一台新电脑。（着重点是现在有了一台新电脑）
(3)两种时态构成形式上的区分。
①一般过去时的谓语动词用过去式，而现在完成时的谓语基本构成是“助动词have/has＋动词的过去分词”。
The film started at 7 0'clock.电影在7点钟开始的。
He has been a teacher for many years.他已经做教师许多年了。
②一般过去时通常与表示过去的时间状语连用。
如：yesterday，last week，two years ago，just now，in 2002等；而现在完成时则常与just，already，ever，never等副词和these days，this week，since…，for…等表示一段时间的状语连用。
③现在完成时强调的是与现在的关系，如对现在产生的结果或影响等，属于现在时范畴，谈论的是现在的情况。而一般过去时只表示动作在过去某一时刻发生，不表示和现在的关系，现在情况可能已发生变化。
Who opened the door?
谁开的门？（只强调过去开门这一动作，门现在可能已关上）
Who has opened the door?　谁把门开了？（强调门现在依然还开着）
现在完成时不能与明确的过去的时间状语连用。
如：three days ago，last year，yesterday，last Sunday，in 2008等等。如句中有以上这些明确的过去的时间状语，应用一般过去时。另外，过去发生的一个动作，现在情况已经发生了变化，也应用一般过去时。
[注意] 如果这些过去的时间状语前面有since，表示“自过去某一时间一直延续到现在”，应用现在完成时。
He finished reading the book the day before yesterday.他前天看完了这本书。
My cousin has been in Nanjing since 2009.我的堂妹自从2009年就在南京了。
④现在完成时不与when引导的特殊疑问句连用，when后面只用一般过去时表示已发生的动作。但现在完成时可与where，why等疑问词连用。
When did the train leave? 火车是什么时候离开的？
⑤since引导的时间状语从句，后面的从句用一般过去时，只有前面的主句才用现在完成时。
We have known each other since we came to the school two years ago.
自从两年前来到学校我们就互相认识了。
⑥有些时间状语，如this morning，this month，tonight等，既可以与一般过去时连用，又可以与现在完成时连用，但内涵不同。与一般过去时连用时，表示与“现在”无关，时间已成为过去。而与现在完成时连用，则包括“现在”在内。
I saw him this morning.我今天早上看到他的。（时间已不在上午了）
I have seen him this morning.我今天早上看到他了。（说话时间还是上午）
He lived in New York for eight years.他曾在纽约住了8年。（他现在已经不在纽约住了）
He has lived in New York for eight years.他住在纽约已经8年了。（他现在还在纽约居住）

二、疑问词+动词不定式
疑问词也包括疑问代词what, which, who和疑问副词how, when, where。常和此结构连用的动词及动词短语有：know, learn, see, hear, ask, tell, decide, explain, find out, forget, remember, understand 等。
【例句】I don’t know what to say next.我不知道接下来该说什么。
I can’t decide which to take.我不能决定该拿哪一个。
Please tell me how to go there.请告诉我怎样到哪儿。
“疑问词+动词不定式” 结构可以改写成由该疑问词引导的从句。
【例句】I don’t know what to do.
= I do not know what I should do. 我不知道该做什么。
【注意】所有疑问句中，只有why不可以与动词不定式连用。
原则上说，why后不接不定式，不过若不定式不带to，则可用why。即：
Why not go there at once?　为什么不马上去那儿呢？
Why argue with her?　为什么要跟她争论呢？
注意：这类结构通常只用于谈论现在和将来，不用于谈论过去。
你昨天为什么不打扫房间？
误：Why not clean the room yesterday?
正：Why didn't you clean the room yesterday?

三、must & have to 用法
1、must表示说话人的主观思想，强调个人意志和主观的决心。主要用于肯定句和疑问句，“必须，得，要”。
【例句】You must finish your homework today. 你今天必须完成家庭作业。
must 的否定形式must not表示禁止，“不能，不允许”。
【例句】You must not smoke here.你不能在这里抽烟。

2、have to 表一种客观的需要，“不得不”。侧重于客观上的必要，强调客观条件作用的结果。
【例句】It is getting dark. He has to go home now. 天快黑了，你现在得回家了。
have to 的否定形式do not have to, 相当于need not 。
【例句】They do not have to buy a computer at the moment.他们目前没有必要买电脑。
注意：must 还可以表示肯定猜测，意思是 “一定” 。否定的猜测是can’t。
【例句】You must be hungry after all that walking.走了那么远的路，你一定饿了吧。
That can’t be Lucy. She has gone to American.那肯定不是Lucy，她已经去了美国。

四、enough to do...和too...to...句式
1：be+adj.+enough+to do sth.表示“（某人、某物）足够做某事”
例如：I’m tall enough to reach the top of the tree.
【拓展句型】be+adj.+enough+for sb.+to do sth.表示对某人来说“（某人、某物）足够做某事”
1. enough作形容词，意思是“足够的;充分的”。作定语置于被修饰的名词前后均可，前置时强调enough，后置时强调被修饰词。如：I have enough books now. = I have books enough now.

2. enough作副词的意思是 “十分地;充分地;足够地;充足地”，置于被修饰的形容词或副词之后，常与不定式或介词for连用 ，在句子中作状语，表示程度。
如：Mum, I think I’m well enough to get back to school.

2：too...to...结构和用法
(1). too... to...表示“太……而不能……”。too 的后面接形容词或副词的原级，to 的后面接动词原形。too... to...句型是简单句。如：He is too young to join the army.

3. too... to... 结构与enough...to... 结构的相互转换
他太小了不能上学。（三种）
He is too young to go to school.
=He is not old enough to go to school.
=He is so young that he can’t go to school.

这个房间太小了十个人住不下。（四种）
The room is too small for ten people to live in.
=The room is not old enough for ten people to live in.
=The room is so small that ten people can’t live in it.
=It’s such a small room that ten people can’t live in it

五、It is +adj+of/for sb to do sth
1) It is+ adj.+ for…+动词不定式
“It is+形容词+for…+动词不定式”可以用来具体说明正在谈论的事情。在该句型中，it是形式主语，for后面所引导的人或物是动词不定式的逻辑主语，for sb./sth. to do sth.在英语中通常称为动词不定式的复合结构。其中的形容词用来说明不定式的特征，而不是说明人的特征或性格。用于该句型的常见形容词有：hard，difficult，easy，important, interesting, dangerous, possible, 'impossible, meaningful, comfortable, uncomfortable等。
如：It's difficult for you to pass the exam.对你来说通过这次考试是困难的。

2) It is＋形容词＋of…＋动词不定式
“It is+形容词+ of…+ 动词不定式”结构用来对某人的品质、性格等作出评价，其中的形容词必须是表示人的品质、性格等的形容词。it是形式主语，没有实际意义。
该结构中的sb.和(not) to do sth.有着逻辑上的主谓关系，所以该句型又可以转换成“sb.+ be+ adj.+(not) to do sth.”。用于该句型的常见形容词有：careless，careful，clever, foolish, good, kind, nice, polite, impolite, rude, selfish, generous, wise, silly, modest, proud, thoughtful等。
如： It's very nice of you to give me a gift. =You are very nice to give me a gift. 你送给我礼物，你真好。
It is silly of you not to forgive others for their mistakes.
=You are silly not to forgive others for their mistakes.你不原谅别人的错误是愚蠢的。

六、被动语态特殊考点
1. 不用于被动语态的情况
（1）不及物动词不用于被动语态，如appear, rise, come out, happen, occur, lie, take place,break down、run out等不及物动词不能用于被动语态。
（2）表状态动词不用于被动语态，常见的有：hold, have, cost, contain, become, look like等。
例句：Great changes have taken place in my hometown in the past ten years.
My money has run out. 我的钱用光了。

2. 主动形式表被动含义
（1） 某些感官动词和系动词接形容词可以表示被动意义。
例句：The coffee smells good.
（2） 某些作表语的形容词后，用不定式主动形式表示被动意义。
例句：I have a lot of homework to do.
（3） need, require, want等作行为动词时，“need/want / require +doing”表被动，等同于“need/want / require + to be done”结构。
例句：My bike needs fixing.=My bike needs to be fixed.
（4） write, sell, wash和read和副词连用，主动语态表被动意义。）
例句：The pen writes well.
易错点：The books sell well.
The books are sold out. （书卖得好是sell well，书卖光了是be sold out）

3.主动变被动中的特殊结构
主动形式
被动形式
see/hear sb. do sth.
be seen/heard to do sth.
see/hear sb. doing sth.
be seen/heard doing sth.
make sb. do sth.
be made to do sth.
使役动词see, hear, make, let等在主动语态中常跟不带to的动词不定式做宾语补足语，但转变成被动语态时，to要还原。

【巧学妙记】
一感：feel
二听：hear, listen to
三让：let, make, have
四看：see, watch, notice, look at
例1.The boy was made to clean streets without pay in the old days.
例2.These children are seen to dance.

七、过去进行时
概念：过去进行时表达的是过去的某个时间点或者过去的某个时间段正在发生的事情。
过去进行时的重点在于：区分一般过去时；
‚掌握时间状语从句中引导词when和while的区别。

过去进行时的标志词：
1. 过去具体的时间点：at 7:00 yesterday; at that moment; at that time；
2. 过去具体的时间段：from 2:00 to 4:00 yesterday; from April to June last year;
the whole afternoon yesterday; all the time yesterday; those years等
3. when和while引导的复合句区别
例1. The earthquake happened when/while I was sleeping.
例2. The telephone rang when/while I was sweeping the floor.
例3. I was sleeping when the earthquake happened.
例4. He was putting in a light when I entered the room.
例5. My mother was cooking while my father was watching TV.
【拓展】
(1) while还有“然而”之意，主从句形成对比。
(2) when有“就在此时”之意，相当于and at that time。
例1. He likes living in the city while I like living in the countryside.
例2. I was going out when my friend Jack came to play chess with me.

总结：
1. when和while引导的复合句到底是用一般过去时还是过去进行时要看语境；
2. while引导的从句一定要用进行时态，可以引导主从句都为进行时的复合句；
3. when引导的从句可以用一般过去时也可以用过去进行时，但是不能引导主从句都为进行时的复合句。

过去进行时常考的语境总结：
1. 有人问过去的某个时间为什么没有做某事，如昨天我给你打电话你为什么没接，今天早上我跟你打招呼你怎么不搭理我，早上开会的时候你怎么没来，回答一律用过去进行时。
例. ---Why didn't you came to the party yesterday evening?
---I was looking after my little sister.

2. 有人问某事做完没，答曰没做完或不知道，接下来补充一句话表达过去的某个时间还是在做的。
例. ---Have your mother finished reading the book?
---I'm not sure. She was reading this morning.

八、动词不定式用法
① 主语 + vt. (及物动词) + to-v (动词不定式)
want, decide, wish, hope, choose, refuse, would like, expect, …
He decided to go there himself. 他决定亲自去那儿。
② 主语+ vt. (及物动词) + to-v (动词不定式)
stop, go on, remember, forget, start, begin, …
Please remember to bring the book to school next time.请记住下次把书带到学校来。
③ 主语 + vt.(及物动词) +it + adj.(形容词) + to-v (动词不定式)
find, think, make, feel, …
The Internet makes it easy to get much new information in a short time.
④ 主语+ vt.(及物动词) +sb./sth.+ (not) + to-v (动词不定式)
get, allow, encourage, beg, wait for, warn, ask, want, would like, tell, wish, expect, invite, …
It’s raining hard now. Let’s wait for the rain to stop. 雨下得很大，让我们等雨停下来。
⑤ 主语+ vt.(及物动词) +sb./sth.+ (not) + v (动词原形)
feel, listen to, hear, let, make, have, see, watch, look at, notice, …
The workers was made to work twelve hours a day. 工人们被迫每天工作十二小时。
⑥ 主语+ vt.(及物动词) +sb./sth.+ 疑问词 + to-v (动词不定式)
teach, show, know, …
I don’t know whether to go there. 我不知道是否去那儿。

九、祈使句
1. Do型(即:动词原形(+宾语)+其它成分)。如:Please have a seat here.
　　有的祈使句在意思明确的情况下,动词可省略。如:This way, please. = Go this way, please. 。
2. Be型(即:Be + 表语(名词或形容词)+其它成分)。如:Be a good boy! 要做一个好孩子!
3. Let型(即:Let + 宾语 + 动词原形 + 其它成分)。如:Let me help you. 让我来帮你。

用"Let\'s"时，把谈话者的对象包括在内；用"Let us"时，并不包括对方，如：
　　Let's try it, shall we?
　　Let us do it by ourselves, will you?

祈使句与并列连词and与or 连用时可以表示条件。
Work harder, and you will catch up with your classmates.

九、反身代词
第一人称
第二人称
第三人称
单数
复数
单数
复数
单数
复数
myself
ourselves
yourself
yourselves
himself/herself/itself
themselves
（1）作动词或介词的宾语：经常在enjoy, teach, hurt, buy, introduce, seat, dress, express, amuse, behave等动词和by, for, to, of等介词后作宾语。如：
He is teaching herself English.她在自学英语。
She was talking to herself.她自言自语。
He lives by himself in the country.他独自住在乡下。
（2）作主语或宾语的同位语：主要起加强语气的作用，译作“亲自，本身，本人”。如：
The work itself is easy.这工作本身很容易。(itself作主语the work的同位语)
（3）作表语：在be, feel等系动词后作表语，表示身体或精神状态处于正常。如：
I’m not myself today.今天我感觉不舒服。
I am feeling myself again.我觉得健康如昔。

十、形容词和副词的比较级和最高级
比较级前的修饰语：still, even, a little, a bit；much, a lot, far
形容词的比较等级常见句型：
A=B A+ V + as + adj./adv. + as + B （与……一样）
He is as tall as I/me. 他和我一样高。
A≠ B A + V + not + as/so + adj./adv. + as + B （与……不一样）
They didn’t do as/so much work as you did. 他们干得事没有你多。
I’ve never seen as/so old a car as this.我从来没有见过像这样旧的车。
A > B 或A < B A + V + 比较级 + than + B （比……更……）
Tom is two years older than his brother. 汤姆比他的弟弟大两岁。
Our classroom is bigger than theirs. 我们的教室比他们的大。
表示程度的递增主语 + V + 比较级+ and+比较级 (…越来越…)
主语 + V + more and more+ +adj./adv. (…越来越…)
The days are getting shorter and shorter.白天变得越来越长了。
Our country is becoming more and more beautiful.我们的国家变得越来越美了。
表示两种情况同时变化
The+ 比较级+ 主语+ V + …，the+ 比较级+ 主语+ V + …(…越…越…)
The more we get together, the happier we’ll be. 我们聚得越多，我们就会越高兴。
The harder you study, the better you’ll be at English.你学习越努力，你的英语成绩越好。
主语+ be +one of the+ 最高级 + n.(pl.) + in/of… (…是最…之一)
Beijing is one of the oldest cities in China.北京是中国最古老的城市之一。
主语+ V。+ the+ 最高级 + in/of… (…最…)
Ann studies hardest of all the girls in our class.安妮是我们班学习最用功的学生之一。
主语+ V。+ the+ 比较级 + of the two… (…较…的)
Lily is the taller of the twins.莉莉是这两个双胞胎中较高的那个。
主语+ V。+ 比较级 + than + any other +n. (单数) + in… (…比任何其他的更…)
主语+ V。+ 比较级 + than + any of the other +n. (复数) + in…(…比任何其他的更…)
He is taller than any other student in his class.他比他班级中其他的任何学生高。
= He is taller than the other students in his class.
= He is the tallest students in his class.
A+ V + the same （size/ colour/ age...）as + B （A与B一样）
My uniform is the same as Simon’s uniform. 我的校服和Simon的校服一样.
Millie’s pencil box is the same size as Amy’s pencil box. 我的铅笔盒和Amy的铅笔盒一样大。

十一、宾语从句三要素
1）连接词：
1.肯定动词后（know, think, believe, be sure等）用连接词that
2.在疑问代词后（wonder, doubt, can you tell me…?, be not sure, not know）后面用if，whether或者特殊疑问词

2）语序：
在宾语从句中用陈述句语序
疑问词+主语+动词
I wonder where he is from/what he likes
What’s wrong/the matter?本身就是陈述句语序，不需要再改语序

3）时态：
1.主句是一般现在时，从句可以用任何时态，但不能用过去完成时和过去将来时
I know Jim watched TV last night
2.主句是一般过去时，从句必须用过去的相应时态
Tom told me Lucy was swimming then.
Tom told me if he had time, he would go there
注意分析主句时态：
I have been told that……
He is often told…..
It is said that….

十二、 状语从句
时间状语从句
(1) 时间状语从句常用when, as, while, before, after, since, till, until, as soon as等连词来引导。
例如：
It was raining hard when I got to school yesterday.
While he was doing his homework, the telephone rang.
As he walked along the lake, he sang happily.
He had learned a little Chinese before he came to China.
After he finished middle school, he went to work in a factory.

(2) 在时间状语从句里，通常不用将来时态，用现在时态表示将来的动作或状态。例如：
I’ll ring you up as soon as I get to New York.
I will tell him everything when he comes back.
He won’t believe it until he sees it with his own eyes.

(3) not…until/ till 直到……才
…till 直到……为止
①until表示动作、状态的持续，强调“一直到……为止”，或强调某个动作或状态一直持续到另一个动作或状态出现之前。常与表示延续性动作的动词连用。
例：I waited until three o’clock, but he didn’t come.

②not … until表示“到……为止；直到……才”，常与表示瞬间性动作的动词连用。
例：The children didn’t come home until it was dark.

(4)when , while, as的区别和联系
1）在when引导的时间状语从句中，动作可以是表示延续的(长动词)，也可以是表示瞬间的(短动词)；
2）while引导的从句中，动作一定是表示延续的（长动词）.
例： I was watching TV when Tom came in.
Tom came in while I was watching TV.
3）as用于表示同一个人的两种动作交替进行,指一边.......一边.......
例：The girl sings as she goes to school.
4）表示两个同步发生的动作或行为,意思是随着......的发展
例： As time went on / by, she became more and more beautiful .
It’s getting colder and colder as the winter comes.
注意: while 除了可以做“正当...时候”之意，还可以表示转折，意思是“然而”。还可以作名词讲，“片刻之意”。如：
Some people waste food while others haven't enough. 有些人浪费粮食,然而有些人却吃不饱。
I haven’t seen her for a long while. 我好久没有看见她了。
(5)since的考查
since引导的时间状语从句，表示主句动作开始的时间，译为“自….以来”。主句常用现在完成时，从句用一般过去时。此外也有： It has been…since从句；It is +一段时间+since从句。
例：He has taught us Maths since he came here.
It’s ten years since I worked in the hospital.
Where have you been since I saw you last？
注意：对 since 引导的时间状语提问要用how long。

because, since与as引导的原因状语从句
(1). because引导的原因状语从句
I did not go to school yesterday because I was ill.我昨天没去上学，因为我生病了。
Because it was raining,we had to stay at home.因为下雨我们只好待在家里。

A. because表示“因为”，表示动作发生的直接原因，语气很强，常用来回答why引导的疑问句。
--Why doesn’t he go with us?他为什么不跟我们一起去？
--Because he’s too tired today.因为他今天太累了。
B. 在一个英语句子中，so和because不能同时出现。
Because my bike was broken,I went to school by bus today.（√）
Because my bike was broken,so I went to school by bus today.（×）

(2) since和as引导的原因状语从句
相对于because而言，since和as的语气较弱。
since与as的用法大体相同，表示附带说明的“双方已知的原因”。由这两个词引导的原因状语从句通常位于句首。
Since it is late,I shall go home right now.（由于）时间不早了，我得马上回家了。
As it is raining,you’d better take a taxi.因为在下雨，你最好乘出租车。

条件状语从句
(1)条件状语从句通常由if, unless引导条件状语从句时，一般遵循主将从现的原则。如果主句是一般将来时，情态动词加动词原形或祈使句时，状语从句用一般现在时。
例： I’ll help you with your English if I am free tomorrow.
Don’t leave the building unless I tell you to.
You mustn’t be late, if you want to go there with me tomorrow.
(2)“祈使句 + and (or)+ 陈述句” 在意思上相当于一个带有条件状语从句的复合句。例如：
Hurry up, or you’ll be late. =If you don’t hurry up, you’ll be late.
Study hard and you will pass the exam. =If you study hard, you will pass the exam.

结果状语从句
结果状语从句由so…that, such…that引导。
so…that与such...that的用法区别
1）在由so...that引导的结果状语从句中，so是副词，与形容词或副词连用。
其结构是: “...so + 形容词（副词）+ that + 从句”。
例 The hall is so big that it can hold 2,000 people.
He spoke so rapidly that we could not clearly understand him.
注意：若so后面的形容词后跟单数可数名词，也可用如下结构：
so ＋形容词＋a／ an +单数可数名词＋ that从句
例：This is so wonderful a film that I will never forget it.

2）在由such…that引导的结果状语从句中，such是形容词，它修饰的可以是单数或复数可数名词，也可以是不可数名词；名词前面可以带形容词，也可不带。如果是单数可数名词，前面需加不定冠词a或an。其结构有以下几种：
such a／ an ＋形容词＋单数可数名词＋ that从句
such＋形容词＋复数可数名词／不可数名词＋that从句
例：It was such a hot day that nobody wanted to do anything.
This book is written in such easy English that beginners can understand it.
They are such fine teachers that we all hold them in great respect.

3）如果名词前有many, much, little, few等词修饰时，只能用so, 不用such。
例：Soon there were so many deer that they ate up all the wild roses.

4）so…that和such...that两种结构的互换
例：It was such a wonderful film that all of us wanted to see it again.
=The film was so wonderful that all of us wanted to see it again.
It is such an important match that nobody wants to miss it.
=The match is so important that nobody wants to miss it.
当that引导的结果状语从句为肯定句时，so…that….可以与be…enough to do转换；当从句为否定句式，可以与too…to….或be not….enough to do转换，从而使复合句变为简单句。
例：Peter is so tall that he can reach the apple on the big tree.
= Peter is tall enough to reach the apple on the big tree.
The boy is so young that he can’t look after himself.
= The boy is too young to look after himself.
=The boy is not old enough to look after himself.

目的状语从句
目的状语从句通常由 so that, in order that（为了，以便）引导。例如：
We started early so that we could catch the first train.
He studies hard so that he could work better in the future.
We used the computer in order that we might save time.

让步状语从句
(1)让步状语从句通常由although, though等连词引导。例如：
Though he is young, he knows a lot.
Although I am tired, I must go on working.
注意：although只能用在句首，而though既可以放句首也可以放句末。
(2)although(though)不能和but用在同一个句子中。例如：
Though it was raining hard, but he still went out. （╳）
正确说法：Though it was raining hard, he still went out.或It was raining hard, but he still went out.