作者：徐广联
出版社：华东理工大学出版社
格式: AZW3, DOCX, EPUB, MOBI, PDF, TXT
名师英语语法课堂：状语从句试读：
作者简介
徐广联
南京理工大学教授，研究方向为英美文学和翻译，醉心于英语教学，痴迷于英语语法。根据其毕生研究及教学经验，编写畅销经典语法书《大学英语语法——讲座与测试》及《当代高级英语语法》。《大学英语语法——讲座与测试》一书在广大英语学习者之间广受好评，成为众多学子英语学习道路上的必备工具书，也成为众多英语教师难得的案头参考书。
内容提要
状语从句（Adverbial Clause）是英语语法中的一个重要门类，掌握好定语从句的使用方法，可以使你分析文章更容易，也能够写出很好的句式。
状语从句可以区分9大类：时间状语从句、地点状语从句、条件状语从句、原因状语从句、让步状语从句、比较状语从句、方式状语从句、目的状语从句和结果状语从句。
全书针对每一类状语从句，都提供了该类从句的使用方法、常用的衔接词及海量的例句，以助于读者更全面地理解状语从句。全书内容详实，讲解细致，例句丰富，掌握全书内容，状语从句的正确使用完全没问题。
状语从句（THE ADVERBIAL CLAUSE）
一、引导状语从句的连词分类表
二、时间状语从句
1.when，whenever，as，while和now
when表示某个具体的时间，所引导从句的动作或是与主句的动作同时发生，或是先于主句动作。when可指一段时间，也可指一点时间，既可表示一时性的动作，又可表示持续性的动作。
whenever指的是“任何一个不具体的时间”。as所表示的动作与主句动作同时发生，具有延续的含义，一般同延续性动词连用，也可同短暂性动词连用，指短暂情况。表示相随渐变的情况，常用as，常译为“一边……一边，正当……的时候”。while表示持续性的动作或状态，主句的情况发生在while从句持续或因反复而持续的过程中，一般不表示一时性或短暂性的动作。as和while可译为“一边……一边……，正当……的时候”。now可以表示“在……之际，在……时”。例如：
He entered the room when/while/as the meeting was going on.正当开会的时候他走进了房间。（指一段时间）
When she comes，I shall tell her to wait for you.她来的时候我会告诉她等你的。（指一点时间，不能用while）
I learned French when I was young.我的法语是年轻时学的。（主句持续，从句持续）
Stop singing when the bell rings.铃一响就不要唱了。（主句短暂，从句短暂）
I was cooking supper when she arrived.她来到时我正在做晚饭。（主句持续，从句短暂）
Let's go boating when the moon has risen.月亮升起后我们去划船吧。（主句动作后于从句动作）
When you come back，you'll find the appearance of the city greatly changed.你回来后将会发现城市的面貌发生了巨大变化。（主句动作后于从句动作）
Her grandma died when she was eleven years old.她11岁那年祖母去世了。（主句短暂，从句持续）
I had hardly stepped in the office when the telephone rang.我刚刚进办公室，电话就响了。（主句动作先于从句动作）
Perhaps，this scene will come back to you years after when you sit alone at sunset like this.也许，多年后的一个黄昏，像现在，你一人独坐的时候，会想起眼前的这一刻的。（主句动作与从句动作同时发生）
He told us his adventures in the Arctic as we went along.我们一边走着，他一边给我们讲他在北极的历险故事。（主句动作与从句动作同时发生）
As time passed，things seemed to get worse.随着时间的推移，情况似乎变得更糟。（相随渐变）
She glanced at me curiously as I opened the door.我开门时，她用好奇的目光打量着我。（从句短暂）
The sun was sinking as we turned for home.我们回家时，正夕阳西下。（主句延续，从句短暂）
She rose as I entered.我刚一进来，她就站了起来。（主句短暂，从句短暂）
As it grew darker it became colder.天渐黑，越发冷起来了。（相随渐变）
As time goes on，we become wiser and wiser.时光流逝中，我们变得越来越明智了。（相随渐变）
His anger grew as he talked.他越说越生气。（相随渐变）
A touch of frustration and helplessness comes over me as I realize how time flies.时光如梭，我只觉得三分怅惘，几分无奈。
As/While Jim was reading，Jack was writing.吉姆阅读的时候，杰克在写东西。（指一段时间）
As/When he finished the speech，the audience burst into applause.他讲话结束的时候，听众掌声雷动。（指一点时间）
I saw the sun as it went down behind a blue line of mountains.我看着太阳落到了大山蓝色轮廓的后面。
He arrived while we were having dinner.他来的时候我们正吃饭。
Make hay while the sun shines.趁着天晴好晒草。（趁热打铁）
Never get on or off a bus while it is in motion.公共汽车未停稳时，不要上车或下车。
You carry on with the work while I have a rest.我休息时，你把这工作做一下。
While she ate she grew more restless.她吃着吃着越发不安起来。【提示】
①while还可以作并列连词，引导并列分句，相当于whereas，表示对比，可译为“……而……，……但是……”，有时相当于although（尽管）。例如：
I am fond of English while he likes maths.我喜欢英语，而他却喜欢数学。
While she is a likeable girl she can be extremely difficult to work with.她虽然是一个可爱的姑娘，但有时却很难共事。
The west is veiled in rain while the east enjoys sunshine.东边日出西边雨。
While I admit that the problem is difficult，I don't think that it can't be solved.尽管我承认这个问题很难，但我并不认为无法解决。
②在现代英语中，while从句的谓语偶尔也可用终止性动词。例如：
Frank put the magazine on the shelf while he finished reading.弗兰克读完那本书后，就把它放回到架子上。
③when有时表示“虽然，尽管”的含义，相当于although；有时具有“既然考虑到”的含义，相当于since；when还可作“如果”解，相当于if。例如：
He walked when he might take a taxi.尽管他可以乘出租车，不过他还是步行。
How can I help them when they won't listen to me？既然他们不听我的话，我怎么帮助他们呢？
They kept digging when they must have known there was no hope.虽然他们明知没有希望，但还是在不停地挖。
How can we finish it before sunset when you won't help？要是你不肯帮忙，我们哪能在日落前做完呢？
④when还可用作并列连词，表示“在那时，然后”。例如：
They are longing for New Year's Day，when they can have a few days'holiday.他们渴望着新年的到来，那时，他们可以有几天的假期。（when=and on New Year's Day）
She came on Monday，when I was busy doing an experiment.她星期一来的，那天我正忙着做实验。（when=and on Monday）
She will stay here till Friday，when she will start for New York.她将在这里待到星期五，然后去纽约。（when=and then，after which）
The President will visit Shanghai in October，when he will deliver a speech in Fudan University.总统将于10月前往上海，届时将在复旦大学发表演讲。
I was walking along the road when suddenly someone patted me on the shoulder from behind.我正在路上走着，这时忽然有人从后面拍拍我的肩膀。
⑤when引导的从句还可作表语。例如：
The time was when we were happy and gay.那时候我们无忧无虑。
That will be when you are rich.那要等你富有之后。
⑥when可以表示对比，意为“而”。例如：
His hands were suddenly uncertain and awkward，when they had held things surely before.过去他拿什么都是很稳当的，现在他双手突然变得笨拙失灵，不听使唤。
⑦“in+动名词”所表示的时间概念。
这种结构相当于由when或while引导的从句，in含有when或while的意思。例如：
In going through the forest，he found a lot of rare plants.他穿过森林时，发现了许多许多珍稀植物。
=When he was going through the forest，he found a lot of rare plants.
In crossing the river，he came among new natural features.过河时，他见到了新的自然景观。
=While he was crossing the river，he came among new natural features.
考察下面一个歧义句：
He didn't come to see her when she asked.
=When she asked，he didn't come to see her.她要他来，但他并没有来看她。
=He came to see her，but not at the time she asked him to come to see her.他来看她了，但并不是在她要他来的时候。
2.before和after
before和after表示的是两个时间或两个事件之间的先后关系。before引导的从句的动作通常发生在主句动作之后，如果从句是过去时，主句一般要用过去完成时。after引导的从句的动作通常发生在主句动作之前，如果主句用过去时，从句要用过去完成时。例如：
They had got everything ready before I arrived.在我到达之前他们已经把一切都准备好了。
After he had worked in the factory for ten years，he went abroad.他在这家工厂工作了10年后就出国了。
It was not long before he sensed the danger of the position.（not〈...〉long...意为“不久……就”，before有时也可换为when，但主句主语是it时，只能用before，不用when，如上句）【提示】如果不强调时间的先后，或是因为从句中使用的是某个状态动词，after和before句子结构中的谓语动词也可以都用一般过去时。例如：
He arrived after the game started.比赛开始后他才到达。
She did not understand me before I explained it to her.在我向她解释之前，她不理解我的意思。
3.no sooner...than和hardly/scarcely...when/before
这几个连词词组都是表示主句和从句动作随即相继发生，意为“一……就，刚刚……就”，主句动词通常用过去完成时，但也有用一般过去时的情况。如果no sooner，hardly或scarcely位于句首，主句要倒装，即把had放在主语前。例如：
He had hardly gone to bed when the door bell rang.他刚刚睡下，门铃就响了。
No sooner had he got off the train than his daughter ran towards him.他刚一下车，女儿就跑了过来。
Scarcely was she out of sight when they came.她刚一走远他们就来了。
The words were scarcely out my mouth before Lisa cried.我的话刚出口莉萨就哭了起来。【提示】hardly...when和scarcely...when有时可同not...before换用。例如：
They had hardly talked for half an hour when she entered.他们才谈了不到半小时她就进来了。
=They had not talked for half an hour before she entered.
4.as soon as，the moment，directly，immediately，instantly，once和the instant等
这几个连词引导的从句都表示从句动作一发生，主句动作随即发生，通常译为“一……就”。instantly语气最强，immediately次之，directly又次之。
另外，the second，the minute，the instant，every time，any time，next time，the first time，the last time，the day，the month，the week，the year，the morning，the afternoon，the entire time，the night，all the time等亦可作连词，引导时间状语从句。例如：
I shall come as soon as I've finished supper.我一吃完晚饭就来。
They told me the news immediately they got the message.他们一得到口信就把消息告诉我了。
She came to the scene the moment she heard of the accident.她一听说出事了，就立刻来到了现场。
Every time he walked by the lake，he thought of his childhood life.
She was lost in thought all the time they were discussing the matter.
I must have stared at the clock the entire time he was gone.在他走后的那整段时间里，我肯定一直在盯着时钟。
They carved their first date on the headboard the night they married.他们新婚之夜就在床头板上刻下了他们的第一个日期。
Our greatest glory consists not in never falling，but in rising every time we fall.我们的了不起，不在于我们永远不败，而在于我们跌倒了能爬起来。【提示】
①immediately，directly，instantly，once等可以用作连词，也可以用作副词。比较：
She went to see him directly she got the letter.她一收到信就去看他了。（连词）
She went to see him directly after she got the letter.她收到信后就立即去看他了。（副词）
Instantly the bell rang and the students came into the classroom.很快铃就响了，学生们都进了教室。（副词）
Instantly the bell rang，the students came into the classroom.铃一响，学生们都进了教室。（连词）
②once引导的从句可以表示时间和条件。下面一句有两种意义：
Once you understand this rule，you will have no further difficulty.
=As soon as you understand this rule，you will have no further difficulty.（时间）
=If you once understand this rule，you will have no further difficulty.（条件）
③as soon as引导时间状语从句时，从句谓语根据情况可用一般现在时、一般过去时、现在完成时或过去完成时。例如：
Could you ring me up as soon as he arrives？他一到你就给我打电话好吗？（一般现在时）
As soon as he found a job he would write to you.他一找到工作就给你写信。（一般过去时）
She'll be coming over as soon as I've settled down.我一安顿下来她就会来的。（现在完成时）
He left as soon as he had drunk coffee.他一喝完咖啡就离开了。（过去完成时）
5.till和until
这两个词的意思都是“直到……，一直……为止”，相当于up to the time that，表示一个动作持续到某一时刻或某一动作发生为止，它们引起一个表示一段时间的状语，其后的词或从句表示这段时间的终点，用法相近，但在句首只能用until。在肯定句中，主句要用延续性动词；在否定句中，until和till通常同非延续性动词连用，有时也可同延续性动词连用。not...until和not...before意思相同，表示“直到……才，在……以前不”。
表示过去的动作或状态时，till/until从句用过去完成时（如不强调动作结束的先后顺序，也可用一般过去时），主句用一般过去时；表示将来的动作或状态时，till/until从句用一般现在时，主句用一般现在时或一般将来时。例如：
She stood there till/until he had passed out of sight.她站在那里看着，直到望不见他的身影。
I'll wait till we meet again.我将一直等到我们再次见面。
He had not known the weight until he felt the freedom.获得自由日，方知重压沉。
Until they had finished the work，they did not go home.他们直到工作完成了才回家。（不用till）
He didn't have a girlfriend until he was thirty.他直到30岁才有女朋友。
直到我回来他才进入房间。
He entered the room until I returned.[×]
He didn't enter the room until/before I returned.[√]【提示】
① 有些动词，既可用作延续性动词，也可用作非延续性动词，因此，其肯定式和否定式均可与until或till连用，但表示的意义往往不同。例如：
He ate until it was dark.他吃饭一直吃到天黑。（eat为延续性动词）
He did not eat until it was dark.他直到天黑才吃饭。（eat为非延续性动词）
②与till，until连用时，be动词既可用肯定式，也可用否定式；表示状态延续的动词如keep，remain，seem常用肯定式；表示变化、完成的动词如become，grow，turn，come，finish，go，reach，return，start，get等要用否定式。例如：
The door remained open until it was dark.门一直到天黑都开着。
The leaves didn't turn yellow until last month.树叶一直到上个月才变黄。（until作介词）
③在表示时间概念时，by与until不同。by表示“到……为止（not later than）”，动作已完成，谓语应是非延续性动词；until表示“直到（某时）为止（up to[the time]）”，谓语应是延续性动词。例如：
你能在星期六前完成工作吗？
Can you finish the work until Saturday？[×]
Can you finish the work by Saturday？[√]
你要把钥匙保存到星期四。
You'll have to keep the key by Thursday.[×]
You'll have to keep the key until Thursday.[√]
④有时候，until从句的位置不同会引起句意的变化，like等词也有这种情况。比较：
I didn't see the temple until I got to the top of the hill.我一直到了山顶才看见那座庙。
Until I got to the top of the hill，I didn't see the temple.我一直到了山顶也没有看见那座庙。
He doesn't enjoy classical music like other students.他并不像别的学生那样喜欢古典音乐。（=He doesn't enjoy classical music，but other students do.）
Like other students，he doesn't enjoy modern music.像别的学生一样，他也不喜欢现代音乐。（=Neither the students nor he enjoys modern music.）
⑤until和till引导的从句谓语不可用shall，will或would。例如：
我们可以在这里待到雨止。
We may stay here until the rain shall stop.[×]
We may stay here until the rain stops.[√]
6.until/till和before的区别
1 相同方面（1）如果主句或简单句中的谓语动词为延续性动词的肯定式，可用until/till和before，但在意义上往往有差别。例如：
She lived in the house until he came back.她在那所房子里一直住到他回来。（到此为止）
She lived in the house before he came back.在他回来之前，她住在那所房子里。（强调“在……之前”）
He worked until five o'clock p.m.他工作到下午5点为止。
He worked before five o'clock p.m.他下午5点之前在工作。
They sat in the waiting room until/before the train pulled in.（2）如果主句或简单句中的谓语动词为非延续性动词的否定式，可用until/till和before，意义上一般没有什么区别。例如：
He didn't leave until/before the rain stopped.雨停了他才离开。
The moon will not come out until/before the clouds disappear.云散了月亮才会出现。
2 不同方面（1）如主句或简单句的谓语为非延续性动词的肯定式，只能用before，不可用until/till。例如：
Before they arrived，the train had pulled out.在他们到达之前，火车已开出了。（不用until）
He can complete the work before sunset.他能够在日落前完成工作。（不用until）（2）如果主句或简单句的谓语动词为延续性动词或状态动词的否定式，要用before，一般不用until/till。例如：
He had not done anything before she came.她来之前，他什么也没有做。
They were not rich before 2010.他们在2010年以前并不富裕。
One does not know the value of health before/until one loses it.人们失去了健康才知道健康的价值。（本句可用before或until，为not...until结构，但not...until强调的是从句，而not...before强调的是主句）（3）在it wasn't until...that强调结构中，不用before。例如：
It wasn't until Sunday morning that I heard the news.直到星期天上午我才听到这个消息。（相当于I didn't hear the news until Sunday morning.）
It wasn't until they had a discussion that they made up their mind.他们直到讨论之后才下定决心。（4）not until可以位于句首，表示强调，句子倒装，不可用before。例如：
Not until yesterday did I see the writer.我直到昨天才见到那位作家。
Not until after the war did they meet.他们直到战后才相见。
7.since
since所引导的从句多用非延续性动词，主句中用完成时态。例如：
Since he graduated from the college，he has worked in this city.他大学毕业后一直在这个城市里工作。
Jack came to see me last month.Since we left school（till then），we had not seen each other.杰克上个月来看我。自从我们离开学校（直到那时），我们一直没有见面。【提示】
①since从句用非延续性动词表示肯定含义；since从句用延续性动词或状态动词的过去式，表示的通常是动作或状态的完成或结束，表示否定意义，即与该动词的词义相反；而延续性动词的现在完成时则表示肯定含义，即与该动词的词义一致。例如：
Since he lived in Nanjing，I have not heard from him.自从他离开南京以来，我没有收到过他的信。（=Since he left Nanjing，...）
Since she was in Yangzhou，she has kept correspondence with her former friends.她离开扬州以来，一直同过去的朋友保持着通信联系。（=Since she left Yangzhou，...）
How long is it since you were in Paris？从你离开巴黎以来有多久了？
It is ten years since he was a mayor.他不当市长已有十年了。
Three years have passed since I smoked.我戒烟已经三年了。
I haven't seen him since we were boys together.自从我们小时候分手后，我就从没有再见过他。
Ten minutes have passed since the rain stopped.雨停了十分钟了。
I have only met him once since I have lived here.自从我在这里住下以后，仅见到过他一次。
比较：
It was fifteen years since she had lived here.从她搬走到那时，已经过了15年。
It is fifteen years since she lived here.她搬走已有15年了。
It is so long since we saw each other.从我们上次见面，已经很久了。（到现在已经很久了）
It had been so long since we had seen each other.从我们在那时之前见面到那一天，已经很久了。（到过去那一天已经很久了）
②作介词时，since后要接时间点，不接时间段，since还用作副词。参阅第四讲。例如：
他自五年前就在写这本书了。
He has been writing the book since five years.[×]
He has been writing the book since five years ago.[√]
He has been writing the book for five years/since he retired.[√]
The old man died long since/many years since.这位老人去世很久了/许多年了。
三、地点状语从句
地点状语从句由 where，wherever和everywhere引导，可以放在主句前，也可以放在主句后。where指“在某个地方”，wherever指“在任何一个地方”，everywhere指“每一……地方”。例如：
You should put the book where it was.你应该把书放在原来的地方。
Wherever you go，you should do your work well.不论到什么地方都要把工作做好。
where除表示地点外，还可以表示条件、对比和让步等。例如：
Where there is love，there is faith.只要有爱情就会有真诚。（条件）
There is never peace where men are greedy.人类贪欲不止，世界和平无望。（条件）
Where I was fascinated by the lecture，my brother showed intolerable indifference.我哥哥对这个演讲毫无兴趣，而我则被深深地吸引住了。（对比）
We want to stay at home，where children would rather spend the holiday in the country.我们想留在家里，而孩子们却宁愿去乡间度假。（对比）
Go where you should，keep on studying.无论你到哪里，你都应该继续学习。（让步）
Unfortunately，where we should expect gratitude，we often find the opposite.遗憾的是，虽然我们本该得到感激，却常常得到的是怨恨。（=though we should...）（让步）
Birth is nothing where virtue is not.如果没有品德，出身再好也白搭。（=Birth is nothing if virtue is not.）（条件）
Persistent people begin their success where others end in failure.不屈不挠者从他人失败的地方获取成功。（表示方面，“在那方面，在那种情况下”）
四、条件状语从句
条件状语从句可位于主句前面或后面。
1.if和unless
if表示正面的条件，意为“如果”；unless表示反面的条件，意为“除非，如果不”（if...not）。例如：
If he doesn't come before 12 o'clock，we won't wait for him.如果他12点前不来，我们就不等他了。
If we want light，we must conquer darkness.我们要光明，就得征服黑暗。
If love between the two can last for long，why need they stay together day and night?两情若是长久时，又岂在朝朝暮暮。
Man cannot discover new oceans unless he has the courage to lose sight of the shore.人类只有鼓起勇气告别海岸，才能发现新的大洋。
I shall go tomorrow unless it rains.除非明天下雨，否则我就要走了。/如果明天不下雨，我就要走了。【提示】
①if引导的从句既可以表示好的条件，也可以表示不好的条件；表示好的条件时，可用providing that，provided that，on condition that等替换；而表示不好的条件时，则不可用这几个条件连词替换，但可以用so/as long as替换。例如：
If it snows tomorrow，we shall play snowballs.如果明天下雪，我们就打雪仗。（好的条件，可用providing that等替换）
If it snows tomorrow，we shall delay our trip to the seaside.如果明天下雪，我们就推迟去海滨旅行。（不好的条件，可用so long as替换）
②比较：
I know nothing about her unless she is fond of swimming.
I know nothing about her except that she is fond of swimming.
第一句的unless表示假设条件，意为“如果她不喜欢游泳，我对她（的其他情况）就一无所知”。
第二句中的except that表示“除去”一个事实，意为“我只知道她喜欢游泳，别的情况不知道”。
③if...not和unless通常是可以换用的。例如：
你如果不很好地掌握英语语法，就写不好英语。
If you don't have a good command of English grammar，you won't write good English.
Unless you have a good command of English grammar，you won't write good English.
但是，if引导从句可以表示非真实条件（用虚拟语气），而unless引导从句一般不可表示非真实条件。下面一句只能用if...not：
We would lend him the money if he didn't break his promise.如果他不违背诺言的话，我们就会把钱借给他。
有时候，在主句后面，unless可以引导一个从句作某种补充说明，通常用破折号同主句隔开，这种用法的unless不可用if...not代替。比较：
They couldn't have found the cave— unless they had found a guide.他们不可能发现那个洞穴——除非他们找到了向导。（他们没能发现那个洞穴）
If they hadn't found a guide，they couldn't have found the cave.他们要不是找到了向导，就不可能发现那个洞穴的。（他们在向导的帮助下发现了那个洞穴）
④if有时相当于when或whenever，可译为“每当……就”。例如：
If I feel any doubt，I inquire.我一有不解的地方就问。
If he was tired，he had a short rest.每当累了，他就休息一会儿。
If the moon shines bright，he takes a walk in the garden.每当月明的夜晚，他就在花园里散步。
⑤if有时相当于since或seeing that，可译为“既然”。例如：
If you like the dictionary，why don't you buy it？你既然喜欢这本词典，为什么不买呢？
If you don't want to stay with us，you may leave at any time.你既然不想同我们在一起，你可以随时离开。
If you don't like the job，why don't you change it？既然你不喜欢这工作，为什么不跳槽呢？
If you want to know，I haven't heard about it.既然你想知道，那就告诉你，我从没听说过这件事。
If you're going out，it's going to rain in the afternoon.既然你要出去，那我就告诉你，下午要下雨的。（It is relevant to tell you that it is going to rain in the afternoon.）
⑥if引导的从句表示对比。例如：
If I am a bad carpenter，I am a worse tailor.我不是好木匠，更不是好裁缝。
If you're the queen，then I'm Napoleon.你不是皇后，正如我不是拿破仑一样。
⑦if可同否定词连用，多以感叹句的形式出现，表示“惊讶”等情感，意为“不是……才怪，这不是”。例如：
Well，if it isn't our old friend Smith！哦，这不是我们的老朋友史密斯吗！
If he isn't the laziest guy on earth！他不是天下最懒的家伙才怪呢！
⑧if可在简单句中表示与事实相反的愿望，谓语动词用虚拟语气，相当于I wish，if only，意为“要是……多好”。例如：
If she were here with me！她要是在这里同我在一起该多好！
If I had been warned！要是有人提醒我该多好！
2.providing/provided（that），supposing/suppose（that），assuming（that），as long as，so long as，on condition that和in case
这些连词（词组）意思相近，有“如果，只要，假如，假使，在……条件下”等意义。例如：
So/As long as you keep on trying，you will surely succeed.只要你继续努力，你就会成功。
Suppose/Supposing（that）I don't have a day off，what shall we do?假如我没有假，那该怎么办?
In case John comes，please tell him to wait.假如约翰来了，请让他等一下。
Assuming that the proposal is accepted，when are we going to get the money?假定这个建议被采纳，我们什么时候能拿到钱?
I don't mind Hill coming with us，provided he pays for his own meals.只要希尔自付餐费，我不介意他和我们一起去。
You may go out providing you do your homework first.你只要先把家庭作业做完，可以出去。
I will lend you the money on condition that you pay it back in one month.我可以借钱给你，条件是你一个月内归还。【提示】in case of后接名词，意为“万一，假如”，in the case of意为“就……来说”。
3.only if和if only
only if引导的从句用陈述语气，意为“只要……”；if only引导的从句要用虚拟语气，意为“但愿……，要是……就好了”。比较：
Only if we persist in carrying out the open-door policy，we will achieve greater success in every field.只要我们坚持改革开放，我们就能在各个方面取得更大的成就。
If only I had known it，I wouldn't have troubled him.要是我早知道那件事，我就不会麻烦他了。
If only that photograph weren't missing！要是那张照片没丢失该多好！
If only it would stop raining.但愿雨停了。
4.without
without也可用作连词，意为“除非，如果不”，相当于unless，引导条件状语从句。例如：
They can't go，without（that）they get permission.他们未经许可是不准去的。
She never goes out without she loses her umbrella.她每次出去总是把伞丢失。
I'd never have known you without you spoke to me.如果当时你没同我说话，我就会永远不认识你的。
5.顺推条件句和逆推条件句
1 顺推条件句
如果条件从句和主句所述为因果关系，或同时表现，或顺着过去、现在、将来的时序，这就是“顺推”。如果条件从句用一般现在时，表示经常一贯的情况，主句即使指过去，也还属于“顺推”。例如：
If he said so，he is a liar.如果他这么说过，他就是一个骗人精。
If she has arrived at the airport，she will be with us soon.如果她已到达机场，她一会儿就和我们在一起了。
If she is always ready to help，he must have asked her to look after the child.如果她一向愿意帮助别人，他一定请她照看孩子了。
2 逆推条件句
如果条件从句和主句所述不是因果关系，而是主观推理，主句情况可能发生在前，这就属于“逆推”。例如：
If he ever won，he must have trained hard.如果他果真赢了，他一定进行过艰苦的训练。
If my son is a genius，I've underestimated him.如果我儿子是个天才的话，那么我原先就低估了他。
If he has a computer，probably he borrowed it from his friend.如果他有电脑，很可能是从他朋友那里借来的。【提示】让步状语从句和原因状语从句后的主句也可以表示逆推。例如：
Though the lights are still on，the meeting may have ended an hour earlier.尽管灯还亮着，会议也许在一个小时前就结束了。
As the river rose，it must have rained last night.河水涨了，昨天夜里一定下雨了。
6.条件概念的其他表示法
1 分词
Born in better times，he would have done credit to the country.如果出生在好的年代，他会为国家作出贡献的。
I have an income large enough to take care of me，living as I do.像现在这样生活，我有足够的收入供养自己。
2 不定式
To look at him，one would think he is only in his thirties.看他的外貌，人们会认为他只有三十几岁。
One would be a fool not to take the opportunity.不抓住这个机会就是个呆子。
3 if，unless引导的省略句
If in doubt，ask a policeman.如有疑问，就问警察。
She won't come unless invited properly.除非体面地邀请，否则她不会来的。
4 从句
Anyone who should do that would be laughed at.谁做那件事都会受嘲笑。
He that would eat the fruit must climb the tree.想吃果子就得爬树。
5 并列句(祈使句+and，祈使句+or)
Give him an inch and he will take a mile.他会得寸进尺。
Stir and you are a dead man.动一动就打死你。
Preserve or we shall fail.坚持一下，不然我们就会前功尽弃。
Climb a storey higher and you'll get a view of a thousand-li.欲穷千里目，更上一层楼。
Conquer the desires，or they will conquer you.战胜欲念，不然欲
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