表示一般过去式的动词通常用动词的过去式形式来表示，而动词的过去式是在动词原形的基础上变化的。
动词的过去式可分为规则动词和不规则动词。

实意动词过去式变化规则:

分类	构成	例句
一般情况下	在词尾直接加ed	ask—asked work—worked
以不发音的e结尾	只加d	love—loved dance—danced
以辅音字母加y结尾	变y为i，再加-ed	try—tried study—studied
以一个元音字母和一个辅音结尾的 重读音节结尾的动词	先双写末尾一个字母，再加ed	stop—stopped permit—permitted
“-ed”的读音规则	1.在清辅音后面读[t],如：help—helped[helpt] 2.在浊辅音或元音后读[d]，如：learn—learned 3.在[t]和[d]后读[id]，如：want—wantedneed—needed

注:以l结尾的动词，尾音节重读时，双写l,如control—controlled;
尾音节不重读时，双不双写都可以，如travel—traveled/traveled。
特例：picnic—picnicked，另外还有很多动词的过去式是不合乎上述规则的，常见的有:
常用的有：
begin—began,         bring—brought,        come—came,        draw—drew,
drink—drank,          drive—drove,          eat—ate,                feel—felt,
get—got,                  give—gave,              go—went,             grow—grew,
have (has)—had,      keep—kept,            know—knew,       leave—left,  
make—made,           read—read,            run—ran,               say—said,
see—saw,                sit—sat

几个特殊实意动词过去式用法:
a.beat的过去式与原形同形：   
beat（打击） 
beat（过去式） 
beaten（过去分词）   
b.lie有规则变化和不规则变化两种，含义不同   
lie，lied, lied（说谎）   
lay, lain（躺，位于）   

c.hang有规则变化和不规则变化两种，含义不同   
hang，hanged, hanged（处绞刑）   
hung, hung(挂，吊)   

d. welcome（欢迎）一词是规则动词，不可误用为不规则动词   
welcome welcomed, welcomed（正）   
welcome, welcome（误）   

e.不要将不规则动词误用为规则动词   
hit（打） 
hit, hit（正）   
hitted, hitted（误） 

实意动词过去式用法基本句式：
1.主+V-ed+宾+其它。。。（肯定句）
2.主+didn't+V原+宾+其它。。。
3.Did+主+V原+宾+其它。。。+？
4.回答：Yes,主语代词+didNo,主语代词+didin't.
5.特殊疑问句：特殊疑问词+一般疑问句。
实义动词的一般过去时态:
肯定句要使用动词的过去式，否定句和疑问句要使用助动词do和 does 的过去式 did.

肯定句为：
主语+动词过去式+宾语    如：
I went home at nine o'clock yesterday.

否定句：
主语+didn't +动词原形+宾语 　如：
I didn't go home yesterday.  He didn't tell me about you.

疑问句：
一般疑问句：
Did +主语+动词原形+宾语
如：Did you go home yesterday?　　
Did you study in the school?
肯定回答： Yes, I did.   　
否定回答：No, I didn't.

特殊疑问句：特殊疑问词+did +主语+动词原型+宾语
When did you finish your homework last night?     　
What did you do the day before yesterday?

并列连词：
主要是用来表示并列关系、选择关系、因果推理关系等。也可用来连接平行的词，词组或分句。

并列连词表示关系及代表实例:
1.表示并列关系
表示并列关系的连词主要含有“和”、“补充”、“增加”等意思。用来表达并列关系的连词有如下几个：
and 和 both...and...二者都
either...or...或者...或者...
neither...nor...既不...也不...
as well as 也、连同
not only...but (also)... 不但...而且...
e.g.
I used to live in Paris and London.
我过去住在伦敦和巴黎。
Both Jane and Jim are interested in pop music.
詹妮和吉姆对流行音乐都很感兴趣。
She is not only kind but also honest.
她不但和蔼而且诚实。
Bob as well as his parents is going on holiday this summer.
鲍勃和他的父母今年夏天要去度假。

2.表示转折关系
常用来表示转折关系的并列连词有如下几个：
but 但是
yet 然而
still 仍然
while 然而
while 然而、偏偏
e.g.
The winter in Beijing is very cold while that of Kunming is warm.
北京的冬天很冷，然而昆明的冬天却很温暖。
I explained twice, still he counldn't understand.
我解释了两遍，然而他却还不懂。

3.表示选择关系
表示选择关系的并列连词：
or 或者
or else 否则
otherwise 否则
neither...nor... 既不...也不...
either...or... 或者...或者...
e.g.
Would you like leave or would you like to stay?
你是想走还是想留？
You can come either on Saturday or on Sunday.
你可以星期六来也可以星期天来。
Neither you nor I nor anyone else believes such things.
不管你我或者其他任何人都不会相信这件事。

4.表示因果推理关系
表示因果关系的并列连词主要有so，for，then，therefore 等。
e.g.
The air here is polluted, so the crops are dying.
这里的空气受到了污染，所以庄稼快死了。
The leaves of the trees are falling, for it's already autumn.
树叶在落下，因为秋天已经到来了。

并列连词注意事项：
并列连词for引导的分句只能放在句尾，前面用逗号隔开，表示补充说明的微弱理由，只是为前面的内容提供判断的理由，有时译为并列的某种形式。
这与because不同，because引导的是一种明确的因果关系，解释原因，常可回答why的提问。
几个特殊并列连词用法：
一、表示并列关系的and，or，well，as，not only...but also... 等连词也有比较活跃的用法。
and 作为并列连词有多重含义，除了可以表示并列关系外，还可以表示顺承、目的、条件、反复等关系。
e.g：He went to market and bought some vegetables.(表示顺承，动作的先后发生）
他到市场买了一些蔬菜。
Come and help me out.(表示目的）
过来帮我一下。
Be careful and you'll make fewer mistakes.(表示条件）
如果仔细，你所犯的错就少。

二、or 与 either...or...
or表示为“否则”的话，前句一般是祈使句，后句用一般将来时。
在表示选择关系时or 与 either...or... 用法相同，但 either...or...更具强调性。
在多个对象进行选择时，可以用A or B or C... , either A or B or C... , neither A or B or C... 。
e.g：Either Jim or Jake or Jeff knows about this.

三、as well as 与not only... but also...
名词+as well as+名词作主语时，强调前面的名词，谓语动词要根据前面的名词而定。
not only...but also...连接名词作主语时，其强调在后者，谓语动词要根据后面的名词而定。
e.g：China as well as many other countries loves peace.
中国与世界上的其他许多国家一样热爱和平。
Not only Bill but also his parents want to go traveling by bike.
不仅比尔而且他的父母都想骑自行车去旅游。
注：当or，neither...nor...，either...or 等连接主语时，谓语动词由or或nor后面的部分而定。
并列连词表示关系:

种类	用法	举例
并列连词	表示转折关系	but, yet等
	表示因果关系	For, so等
	表示并列关系	And, or, either…or, neither…nor, not only.. but also, as well as等

状语从句：
指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。
根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。
状语从句一般由连词(从属连词)引导，也可以由词组引起。
从句位于句首或句中时通常用逗号与主句隔开，位于句尾时可以不用逗号隔开。
状语从句分类:
1、时间状语从句
常用引导词：
when, as, while, as soon as, while, before, after, since , till, until
特殊引导词：
the minute, the moment, the second, every time, the day,the instant, immediately , directly, no sooner … than, hardly …when, scarcely … when
I didn't realize how special my mother was until I became an adult.
While John was watching TV, his wife was cooking.
The children ran away from the orchard(果园) the moment they saw the guard.
No sooner had I arrived home than it began to rain.
Every time I listen to your advice, I get into trouble.

2、地点状语从句
常用引导词：
where
特殊引导词：
wherever, anywhere, everywhere
Generally, air will be heavily polluted where there are factories.
Wherever you go, you should work hard.

3、原因状语从句
常用引导词：
because, since, as, for
特殊引导词：
seeing that, now that, in that, considering that, given that, considering that, as much as, so much as
My friends dislike me because I'm handsome and successful.
Now that everybody has come, let's begin our conference.
The higher income tax is harmful in that it may discourage people from trying to earn more.
Considering that he is no more than 12 years old, his height of 1.80 m is quite remarkable.

4、目的状语从句
常用引导词：
so that, in order that
特殊引导词：
lest, in case, for fear that,in the hope that, for the purpose that, to the end that
The boss asked the secretary to hurry up with the letters so that he could sign them.
The teacher raised his voice on purpose that the students in the back could hear more clearly.

5、结果状语从句
常用引导词：
so that, so… that, such … that,
特殊引导词：
such that, to the degree that, to the extent that, to such a degree that,
He got up so early that he caught the first bus.
It's such a good chance that we must not miss it.
To such an degree was he excited that he couldn't sleep last night.

6、条件状语从句
常用引导词：
if, unless,
特殊引导词：
as/so long as, only if, providing/provided that, suppose that, in case that, on condition that
We'll start our project if the president agrees.
You will certainly succeed so long as you keep on trying.
Provided that there is no opposition, we shall hold the meeting here.

7、让步状语从句
常用引导词：
though, although, even if, even though
特殊引导词：
as(用在让步状语从句中必须要倒装),while ( 一般用在句首 ),no matter …, in spite of the fact that, while, whatever, whoever, wherever, whenever, however, whichever
Much as I respect him, I can't agree to his proposal.
尽管我很尊敬他, 我却不同意他的建议。
The old man always enjoys swimming even though the weather is rough.
No matter how hard he tried, she could not change her mind.
He won't listen whatever you may say.

8、比较状语从句
常用引导词：
as(同级比较), than(不同程度的比较)
特殊引导词：
the more … the more … ; just as …, so…; A is to B what /as X is to Y; no … more than; not A so much as B
She is as bad-tempered as her mother.
The house is three times as big as ours.
The more you exercise, the healthier you will be.
Food is to men what oil is to machine. 食物之于人,犹如油之于机器。

9、方式状语从句
常用引导词：
as, as if, how
特殊引导词：
the way
When in Rome, do as the Roman do.
She behaved as if she were the boss.
Sometimes we teach our children the way our parents have taught us.

状语从句用法:
时间状语从句
(1) when引导的时间状语从句
①.when引导的时间状语从句，其动词既可以是延续性动作的动词，也可以是瞬间性动作的动词，而且可以表示主句的动作和从句的动作同时发生，或者从句的动作发生在主句的动作之前。如：
when you apply for a job, you must present your credentials.
当你申请工作时，你必须递交你的有关证件。（同时）
when the students heard the teacher’s footsteps, they all atopped talking.
当学生们听到老师的脚步声时，他们都停止了讲话。（从句动作发生在前）
② when还可表示just then（正在那时，突然）的意思，此时其所引导的从句只放在主句之后。如：
we were about to start when it began to rain.
我们正要动身，突然天下起雨来。
The game had hardly/scarcely/barely begun when it started raining.
比赛刚刚开始就下起雨来。
(2) as引导的时间状语从句
as引导的时间状语从句其动词的动作是延续性的，而且侧重表示主句和从句的动作并相发生：
We were having breakfast as she was combing her hair.
她梳头时我们在吃早饭。
It will warm up a little bit on Sunday as the cold front passes.
寒流一过，星期日就会有点暖意了。
(3) while引导的时间状语从句
while表示“在某一段时间里”或“在……期间”，其所引导的从句的动作是延续性的，并侧重表示和主句的动作同时发生。如：
When the teacher paraphrased the text in English, the students listened attentively and took notes.
当老师用英语解释课文时，学生们聚精会神地听并做着笔记。
I can learn while I work.
我可以边工作边学习。
(4) before引导的时间状语从句
① before“在……之前”
I have finished my dissertation before my supervisor went abroad.
在我的导师出国之前，我已完成了我的学位论文。
I’ll be back before you have left.
你离开之前我就会回来。
② before“……之后才”
It may be many years before we meet again.
可能要过许多年我们才能再见了。
It was three days before I came back.
他三天后才回来。
(5) as soon as/once/directly/the instant等引导的时间状语从句
as soon as 是最常见的表示“一……就”的从属连词，其他连词还有once，directly，immediately，instantly，the instant (that)，the minute(that) ，the moment(that)等，它们通常都可与as soon as换用。如：
As soon as we got home, the telephone rang.
我们一到家，电话就响了。
I recognized her immediately I saw her.
我一看见她就认出她来了。
Directly the teacher came in everyone was quiet.
老师一进来，大家就静了下来。
(6) hardly...when/no sooner...than引导的时间状语从句
关联从属连词hardly/barely/scarcely...when和no sooner...than的意思是“刚……就”，它们所引导的从句中的谓语动词通常为过去完成时。如：
He had no sooner (no sooner had he)arrived home than he was asked to start on another journey.
他刚一到家，就又要他出另一次差。
No sooner had the words been spoken than he realized that he should have remained silent.
这些话刚一出口，他就意识到自己应该保持沉默。
(7) since引导的时间状语从句
在含有since引导的时间状语从句的复合句中，从句的谓语动词通常为一般过去时，主句的谓语动词通常为现在完成时、过去完成时和一般现在时：
We’ve never met since we graduated from the college.
大学毕业后我们就再没见过面。
Great changes have taken place since you left.
你走了以后，这里发生了巨大变化。
(8) till/until引导的时间状语从句 till和until同义，作“直到……时(为止)”解，till多用于非正式文体，until多用于句首。如：
Donald will remain in college until(till) he finishes his Ph.D course.
唐纳德将留在学校直到完成他的博士学位课程。
I won’t go with you until(till) I finished my homework.
等我做完作业我才和你一起去。
(9) whenever/each time/every time引导的时间状语从句
whenever在引导时间状语从句时作“每当；每次”解，each time和every time与whenever同义，通常可以与它换用。如：
The roof leaks whenever it rains.
每逢下雨屋顶就漏雨。
Whenever certain chemicals are mixed together，heat is produced.
某些化学物质被混到一起时，就会产生热。
Whenever/ Every time/ Each time I met her, she was studying.
我每次看见她时，她总是在学习。

状语从句 - 地点状语从句
(1) when引导的时间状语从句
从属连词where“在（或到）……的地方”
Where there is a will, there is a way.
有志者事竟成。
Put it where you found it.
把它放在原来的地方。
① where 在地点状语从句中，除指地点外，还可指处境等。如：
He said he was happy where he was.
他说他对自己的处境很满意。
It’s your fault that she is where she is.
她今天落到这个地步都怪你。
② 有时地点状语从句中的某些词可以省略。如：
Fill in the blanks with the given phrases. Change the form where necessary.
用所给的短语填空，必要的地方可以改变其形式。
Avoid structure of this kind where possible.
只要可能，就要避免这种结构。
(2) wherever引导的地点状语从句
从属连词wherever“在（或到）……的各个地方”：
You can go wherever(anywhere) you like these days.
这些天你可以去你想去的地方。
Where (Everywhere) they went, the experts were warmly welcomed.
专家每到一处， 都受到热烈的欢迎。
Sit down wherever you like.
你喜欢坐哪儿就坐哪儿。

状语从句 - 原因状语从句
 (1) because引导的原因状语从句
because表示人们不知道的直接的原因或理由，着重点在从句，其所引导的从句，为全句句意的中心所在。
通常用于回答why引出的疑问句，语气最强，除特别强调外，该从句一般位于主句后面。
I didn’t go abrord with her because I couldn’t afford it.
我没有和她一起出国是因为费用太高。
Don’t scamp your work because you are pressed for time.
不要因为时间仓促而马马虎虎。
(2) as引导的原因状语从句
as引导的原因状语从句所传递的通常是已知信息，从句多位于主句之前，通常可以和since换用。如：
As I didn’t know the way，I asked a policeman.
我不认识路，因而问警察。
As it is snowing, we shall not climb the mountain.
由于在下雪，我们不去爬山了。
(3) since引导的原因状语从句
since引导的原因状语从句所传递的通常是已知信息，从句多位于主句之前，通常可以和as换用。如：
Since traveling by air is much faster,they decided to take a plane.
既然乘飞机旅行快得多，他们就决定坐飞机。
Since you won’t help me ，I’ll ask someone else.
你既然不帮我，那我就请别人帮忙。
(4) now(that)引导的原因状语从句
now(that)“因为；既然”，通常可以和since换用。其中that可省去，用来表示一种新的情况，再加以推论。如：
Now(that) you?蒺ve passed your test you can drive on your own.
你既已考试合格，就可以独自开车了。
I do remember，now (that) you mention it.
你这一提，我倒的确想起来了。
(5) seeing (that)引导的原因状语从句
Seeing (that)“鉴于；由于”，通常用于非正式文体。如：
Seeing (that) the weather is bad，we’ll stay at home.
天气不好，我们还是呆在家里吧。
Seeing that he’ s ill，he’s unlikely to come.
(6) in that引导的原因状语从句
in that“因为；基于……的理由”，可以和because换用，多用于正式文体，它所引导的原因状语从句总是位于主句之后。如：
Advertisement is distinguished from other forms of communication in that the advertiser pays for the message to be delivered.
广告不同于其他交际形式，因为登广告的人要为其所提供的信息付费。
I’m in a slightly awkward position, in that he’s not arriving until 10th.
我的处境有点难堪，因为他要十号才来。

状语从句 - 目的状语从句
 (1) in order that引导的目的状语从句
in order that“为了；以便”。多用于正式文体，通常可以与so that换用。如：
You stopped at Hangzhou in order that they could go around West Lake.
他们在杭州停了下来，以便游览西湖。
The expert spoke slowly in order that everyone should understand.
专家讲得很慢，以便人人听得懂。
(2) so (that)引导的目的状语从句
so that“为了；以便”。so that通常可以与in order that换用，它所引导的目的状语从句总是放在主句之后，在非正式文体中，常省略that。如：
Speak clearly so that they may understand you.
你要讲得清楚，他们才听得懂。
She wanted tea ready at seven so she could be out by eight.
她要七点钟备好茶点，这样她八点以前就可以出门了。
(3) in case/for fear (that)/lest等引导的目的状语从句
in case，for fear(that)和lest这三个从属连词都表示否定目的，意思是“以免”,“以防”。
in case多用于英国英语，它所引导的从句中的谓语动词可以是陈述语气形式，也可以是虚拟语气形式；
for fear(that)引导的从句中的谓语带有may，might，should等情态动词；
lest用于正式文体，它所引导的从句中的谓语动词用虚拟语气形式。如：
Take your umbrella with you，lest it should rain.
带上你的伞，以防下雨。
Take your umbrella in case it rains.
带上你的伞，以防下雨。
He took an umbrella with him for fear that it might rain.
他带了一把伞，以防下雨。
状语从句 - 结果状语从句
(1) so that引导的结果状语从句
① so that引导的结果状语从句只能位于主句之后，中间可以有逗号。如：
Suddenly it began to rain heavily，so that it was almost impossible to carry on driving.
突然下起了大雨，几乎无法继续开车。
Linda phoned me in on arrival so that I know she was safe and sound.
琳达到达后给我打了电话，因而我知道她平安无事。
②“so that”既可引导结果状语从句也可引导目的状语从句。
究竟是引导的结果状语从句还是目的状语从句，除了根据句意来判断外，还可根据结构形式来加以判断。
若从句前有逗号，一般为结果状语从句，如果从句中有情态动词，通常则为目的状语从句。如：
They started out early, so that they didn’t miss the train.
他们早早就出发了，所以没误火车。(结果状语从句)
They started out early so that they would not miss the train.
他们早早出发是为了不误火车。(目的状语从句)
(2) so...that引导的结果状语从句
so...that“如此……以致”，that在非正式文体中可以省略，so后面接形容词或副词。如：
She spoke so fast that nobody could catch what she was saying.
她说话如此之快竟没有人听出来她在讲什么。
There is so little time left that I have to tell you about it latter.
现在剩下的时间不多了，我只好以后再给你讲这件事。
(3) such...that引导的结果状语从句
引导结果状语从句的such...that的具体内容是：such+a/an+形容词+名词+that从句。
其中的名词可以是可数名词的单数或复数，也可以是不可数名词。
such+a/an+形容词+单数名词+that从句可换成so+形容词+a/an+单数名词+that从句。如：
The Japanese student made such rapid progress that he soon began to write article in Chinese.
那个日本留学生进步很快，不久就开始用中文写文章了。
The professor told us such a funny story that all the students laughed．
(＝The professor told us so funny a story that all the students laughed.)
教授讲了个很有趣的故事，(以致于)所有的学生都笑了起来。
(4) such that引导的结果状语从句
such that引导的结果状语从句多用于正式文体，主句为“主—系—表”句型。如：
The force of the explosion was such that it blew out all the windows.
爆炸的力量很大，所有的窗户都被炸掉了。
His anger was such that he lost control of himself.
他气得不能克制自己的感情。

状语从句 - 条件状语从句 
(1) if引导的条件状语从句
if可引导非真实条件状语从句(见“虚拟语气”)和真实条件状语从句。如：
If he said that，he can’t be telling the truth.
如果他说了那样的话，他不可能是说实话。
(2) unless引导的条件状语从句
unless引导的是否定条件状语从句，在意义上相当于if...not，而且语气较强，一般不用于虚拟语气。如：
You’ll be late unless you hurry.
你会迟到的，如果不赶快的话。
(3) if only引导的条件状语从句
if only在引导条件状语从句时意为“只要；如果”。如:
I’ll let you use the car if only you keep it in good condition.
只要你把车保养好，我就让你用。
(4) as/so long as引导的条件状语从句
as/so long as意为“只要；如果”。如：
As long as it doesn’t rain, we can play.
只要不下雨我们就能玩。
(5) provided (that)/providing (that)引导的条件状语从句
provided (that)/providing (that)意为“如果；只要”。如：
I will agree to go provided’ providing (that my expense are paid.)
假如为我负担费用，我就同意去。
Providing you promise not to tell anyone else I’ll explain the secret.
状语从句 - 让步状语从句
(1) although/though引导的让步状语从句
although和though，都作“虽然；尽管”解，通常可以换用，although的语气较重。
如果要强调“但是”语气，可使用yet，still或nevertheless来表示“但是”、“依然”或“然而”之意。
Although they have been talking for a long time, he cannot make her believe him.
虽然和她谈了半天，他还是不能让她信任自己。
(2) even if引导的让步状语从句
even if “即使，纵然”，从句表示的是尚未发生的动作或存在的情况。如：
Even if it rains tomorrow，we won’t change our plan.
即使明天下雨，我们也决不改变计划。
Even if I failed again, I will not give up the experiment.
即使我再次失败，我也决不会放弃实验。
(3) even though引导的让步状语从句
even though“虽然，尽管”，从句所表示的是已经发生的动作或存在的情况，通常可以和although/though换用。如：
Even though I didn’t understand a word，I kept smiling.
即使我一个字也不懂，我还是保持微笑。
Even though you say so，I do not believe it.
即使你这样说，我也不信。
(4) much as引导的让步状语从句
much as“虽然，尽管”，通常可以和although/though换用：
Much as I’d like to，I can’t come.
我虽然很想来，但是来不了。
Much as I admire his courage，I don’t think he acted wisely.
我虽然佩服他的勇气，但我认为他这样做是不聪明的。
(5) while引导的让步状语从句
while“虽然，尽管”，多用于正式文体，通常可换作although/though。如：
While I understand your point of view，I do not share it.
我虽了解你的观点，但不敢苟同。
While I sympathize，I really can’t do very much to help.
虽然我很同情，但我确实帮不了什么忙。
(6) whatever/No matter what引导的让步状语从句
whatever和no matter what用法相同，都作“无论什么”解，后者多用于非正式文体。如：
Whatever/No matter what he says，don’t go.
不管他说什么，你都不要走。
We are determined to fulfill the task，whatever/no matter what happens.
不管发生什么了，我们决心完成任务。
(7) whichever/no matter which引导的让步状语从句
whichever和no matter which用法相同，都作“无论哪个”解，后者多用于非正式文体。如：
Whichever/No matter which you buy， there is a six-month guarantee.
不论你买哪个，都有六个月的保修期。
Whichever/No matter which of the two men had stolen her purseBarbara was determined to find them.
不管这两个人是谁偷了她的钱包，芭芭拉决心找到他们。
(8) whoever/no matter who引导的让步状语从句
whoever和no matter who用法相同，都作“无论谁”解，后者多用于非正式文体。如：
You can’t come in， whoever you are.
不管你是谁，都不能进来。
Whoever/No matter who wants to speak to me on the phone, tell him I’m busy.
不管谁要我接电话， 就说我现在正忙着呢。
(9) whereverno matter where引导的让步状语从句
wherever和no matter where用法相同，都作“无论在（或到）哪里”解，后者多用于非正式文体。如：
Wherever/No matter where you go, I’m Right Here Waiting fo ryou.
无论你到哪里，我都依然在这里等着你。
(10) however/no matter how引导的让步状语从句
however和no matter how用法相同，都作“无论如何……”解，后者多用于非正式文体。
However much you regret doing that， there is nothing you can do about it now.
无论你可能多么懊悔你曾经做过的事，现在也无济于事了。
However high it may be，it can’t reach the sky.
它不论有多高，也高不到天上去。
(11) whenever/no matter when引导的让步状语从句
whenever和no matter when用法相同，都作“无论何时”解，后者多用于非正式文体。如：
Whenever I’m unhappy，he cheers me up.
每当我不高兴时，他就给我鼓劲儿。
(12)(no matter) whether...or引导的让步状语从句
whether...or和no matter whether...or用法相同，都作“不论……还是”解，后者的语气强一些。如：
When It Rains or not, we’re playing football on Sunday.
无论下不下雨，我们星期天一定踢足球。
(13) as引导的让步状语从句
as在引导让步状语从句时作“虽然；尽管”和“即使”解，但是它不位于句首，在它前面的可以是形容词、名词、副词等。如：
Strong as you maybe, you cannot lift it.
虽然你可能很有力气，你却无法把它提起来。
Late as it was, they continued to study.
时间尽管不早了，他们仍继续学习。

状语从句 - 方式状语从句
(1) as引导的方式状语从句
as在引导方式状语从句时意为“以……方式；如同……那样”，从句有时是省略句。如：
Do as I say. 要照我说的做。
I did just as you told me. 我正是照你说的办的。
Air is to man as water is to fish. 空气之于人犹如水之于鱼。
(2) as if/as though引导的方式状语从句
as if和as though的用法相同，都作“好像，仿佛”解。如：
二者引导的状语从句往往用虚拟语气，表示与事实相反。as if比as though更为常用。
但也可用陈述语气，表示所说的情况是事实或实现的可能性较大。如：
They looked at me as if ‘as though I were mad.
他们瞧着我好像我发疯了似的。
They look as if/as though they know each other.
他们看来好像互相认识。

状语从句 - 比较状语从句
(1) as...as 引导的比较状语从句
as...as表示同级比较，主句中用形容词或副词的原级形式，从句常常为省略句。如：
We were as fortunate as them (they were)
我们和他们一样幸运。
I hope she will make as much progress as you (have done).
我希望她将取得和你同样的进步。
(2) not so/as...as 引导的比较状语从句
not so/as...as表示同级比较，主句中用形容词或副词的原级形式，从句常常为省略句。如：
That’s not so/as simple as it sounds.
那件事情不像听起来那么简单。
(3) than引导的比较状语从句
than引导的比较状语从句表示同等比较，主句中用形容词或副词的比较级形式，从句常常为省略句。如：
He has lived here longer than I(has lived).
他在这儿住的时间比我长。
They love the girl than(they love) him.
他们爱这个女孩而不爱他。
(4) the..., the...引导的比较状语从句
The more you listen to English, the easier it becomes.
英语听得越多就越容易。