本试题 “The old woman_________sit in front of the house,__________for her son to come back fromthe front.[ ]A. was going to ; waitedB. would ; waitedC. was...” 主要考查您对现在分词
虚拟语气
等考点的理解。关于这些考点您可以点击下面的选项卡查看详细档案。
现在分词的概念：
现在分词（PresentParticiple）(又称-ing形式)，是分词的一种，是非限定动词，即在句子里面不能单独充当谓语，但能充当其它的一些成分（定语，表语，补语和状语）。一般式：doing；一般被动式：being done；完成式：having done；完成被动式：having been done。所有否定式都是在－ing前面加not。
现在分词的用法：
1）做表语：
如：He was very amusing.
That book was rather boring.
很多动词的现在分词都可以作表语：exciting, interesting, encouraging, disappointing, confusing, touching, puzzling.
2）作定语：
上面所出现的现在分词都可以用作定语,修饰一个名词：
如：That must have been a terrifying experience.
I found him a charming person.
现在分词短语还可以放在名词的后面修饰名词,相当于一个定语从句：
如：There are a few boys swimming in the river.
There is a car waiting outside.
3）作状语：
现在分词短语可以表示一个同时发生的次要的或伴随的动作：
如：Following Tom, we started to climb the mountain.
Opening the drawer, he took out a box.
Taking a key out of his pocket, he opened the door.
现在分词短语还可以表示原因，相当于一个原因状语从句：
如：Not knowing her address, we couldn't get in touch with her.
Being unemployed, he hasn't got much money.
现在分词短语还可以表示时间，相当于一个时间状语从句：
如：Hearing the news, they all jumped with joy.
Returning home, he began to do his homework.
Jim hurt his arm while playing tennis.
Be careful when crossing the road.
Having found a hotel, we looked for some where to have dinner.
Having finished her work, she went home.
4）作宾补：
现在分词在一些动词之后可以做宾语的补语：
例如：see, hear, catch, find, keep, have等。
如：I see him passing my house every day.
I caught him stealing things in that shop.
I smelt something burning.
She kept him working all day.
现在分词其他用法解析：
1、现在分词一般式的用法：
现在分词的一般式所表示的动作与主语动作同时发生：
如：When we arrived, we found him sleeping. 我们到达时发现他在睡觉。
Living in the 示的动作也可略早于或迟于谓语动作，但两者之间没有时间间隔：
如：Seeing nobody at home, he decided to leave a note. 发现没有在家，他决定留个字条。
He went home, finding the door locked. 他回到家，发现门是锁着的。当现在分词所表示的动作略迟于谓语动作时，现在分词通常位于句末。
2、现在分词完成式的用法：
现在分词的完成式主要表示发生在谓语动作之前的动作：
如：Having been there once, she knew the place quite well. 由于去过那儿一次，她对那地方很熟悉。
Having failed twice, he didn't want to try again. 他已经失败了两次，不想再试了。
注：（1）现在分词的一般式和完成式均可表示已完成或先于谓语的动作，但有区别：现在分词所表示的动作虽然可以先于谓语动作，但两者之间没有时间间隔，而现在分词的完成式所表示先于谓语的动作则与谓语动作有一定的时间间隔：
如：Locking the door, he went out. 锁好门之后，他就出去了。
Having invited him here to speak, we'd better go to his lecture. 既然我们请了他来作报告，我们最好去听一下。
有时即使是分词动作与谓语动作几乎同时发生，但如果要强调分词动作的完成性，也应用现在分词的完成式：
如：Having bought our tickets, we went into the theatre. 我们买好票后就走进剧场。
（2）现在分词的完成式一般不用作定语：
误：Do you know anyone having lost a cat? 你知道有谁丢了一只猫吗？
误：I want to talk to the person having broken the window. 我想同打破窗户的人谈谈。
若将以上现分词的完成式改为一般式也不可以（因为现在分词作后置定语时通常只表示与谓语动作同时或几乎同时发生的动作，而不能先于谓语动作而发生）：
误：I want to talk to the person breaking the window.
3、现在分词被动式的用法：
当要表示一个被动动作时，现在分词就用被动形式。现在分词的一般式和完成式均有被动式形式：
（1）现在分词一般式的被动式：主要表示现在正在进行的动作，也可表示与谓语动作同时发生的动作：
如：Who is the woman being operated on? 正在动手术的女人是谁?
I saw him being taken away by the police. 我看见他被警察带走。
注：有时现在分词一般式的被动式所表示的动作也可发生在谓语动作之前（此时的现在分词通常用于表示原因，且多为状态动词）：
如：Not having a car, he finds it difficult to get around. 由于没车，她感到行动很困难。
（2）现在分词完成式的被动式：主要表示发生在谓语动词之前且已经完成的动作。
如：The subject having been opened, he had to go on with it. 话题已经开始了，他不得不谈下去。
Having been written inhaste, the book has many mistakes. 这书因写得仓促，所以错误不少。
比较：Being so ill, she can't go to school. 由于病得那么严重，她不能去上学。
Having been ill for a long time, he needed time to recover. 由于病了很长时间，他需要一段恢复的时间。
虚拟语气的概念：
虚拟语气用来表示说话人的主观愿望或假想，所说的是一个条件，不一定是事实，或与事实相反。在条件句中的应用条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。
虚拟语气在条件句中的应用：
一、真实条件句：
真实条件句真实条件句用于陈述语气，假设的情况可能发生，其中if是如果的意思。
时态关系句型：条件从句：一般现在时；主句：shall/will+动词原形
如：If he comes, he will bring his violin.
典型例题：
The volleyball match will be put off if it___.
A. will rain
B. rains
C. rained
D. is rained
答案：B。真实条件句主句为将来时，从句用一般现在时。
注意：1）在真实条件句中，主句不能用be going to表示将来，该用shall, will。
如： （错） If you leave now, you are never going to regret it.
（对） If you leave now, you will never regret it.
2）表示真理时，主句谓语动词便不用shall(will)+动词原形，而直接用一般现在时的动词形式。
二、非真实条件句：
非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。
1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。
a. 同现在事实相反的假设。
句型：从句：一般过去时；主句：should(would)+动词原形
如：If they were here, they would help you.
b.表示于过去事实相反的假设。
句型：条件从句：过去完成时；主句：should(would)have+过去分词
如：If she had worked harder, she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday, he would have prevented me from going.
c.表示对将来的假想句型：
条件从句：一般过去时；主句：should+动词原形
从句： were+不定式；主句：would+动词原形 should+动词原形
如：If you succeeded, everything would be all right.
If you should succeed, everything would be all right.
If you were to succeed, everything would be all right.
三、混合条件句：
主句与从句的动作发生在不同的时间，这时主，从句谓语动词的虚拟语气形式因时间不同而不同，这叫做混合条件句。
如：If you had asked him yesterday, you would know what to do now. （从句与过去事实相反，主句与现在事实相反。）
If it had rained last night (过去), it would be very cold today (现在).
比较if only与only if：
only if表示“只有”；if only则表示“如果……就好了”。If only也可用于陈述语气。
如：I wake up only if the alarm clock rings. 只有闹钟响了，我才会醒。
If only the alarm clock had rung. 当时闹钟响了，就好了。
If only he comes early. 但愿他早点回来。
It is(high) time that It is(high) time that 后面的从句谓语动词要用过去式或用should加动词原形，但should不可省略。
如：It is time that the children went to bed.
It is high time that the children should go to bed.
need“不必做”和“本不该做"”
didn't need to do表示：过去不必做某事，事实上也没做。
needn'thavedone表示：过去不必做某事，但事实上做了。
如：John went to the station with the car to meet Mary, so she didn't need to walk back home.
约翰开车去车站接玛丽，所以她不必步行回家了。
John went to the station with the car to meet Mary, so she needn't have walked back home.
约翰开车去车站接玛丽，所以她本不必步行回家了。(Mary步行回家，没有遇上John的车。)
典型例题：
There was plenty o ftime. She___.
A. mustn't have hurried
B. couldn't have hurried
C. must not hurry
D. needn't have hurried
答案：D。needn't havedone. 意为"本不必"，即已经做了某事，而时实际上不必要。 Mustn't have done用法不正确，对过去发生的事情进行否定性推断应为couldn't have done,“不可能已经”。must not do不可以（用于一般现在时）
特殊的虚拟语气词should 的用法：
1）It is demanded/necessary/a pity+that…结构中的主语从句的谓语动词要用should加动词原形，should可省略。
句型：
如：It is suggested that we(should) hold a meeting next week.
It is necessary that he(should) come to our meeting tomorrow.
2）在宾语从句中的应用在表示命令、建议、要求等一类动词后面的从句中。order, suggest, propose, require, demand, request, insist, command, insist+(should)do
如：I suggest that we(should) hold a meeting next week.
He insisted that he(should) be sent there.
注意：如suggest, insist不表示“建议”或“坚持要某人做某事时”，即它们用于其本意“暗示、表明”、“坚持认为”时，宾语从句用陈述语气。
如：The guard at gate insisted that everybody obey the rules.
判断改错：（错）You pale face suggests that you(should) be ill.
（对）Your pale face suggests that you are ill.
（错）I insisted that you(should) be wrong.
（对）I insisted that you were wrong.
3）在表语从句，同位语从句中的应用在suggestion, proposal, idea, plan, order, advice等名词后面的表语从句、同位语从句中要用虚拟语气，即（should）+动词原形。
如：My idea is that we(should) get more people to attend the conference.
I make a proposal that we(should) hold a meeting next week.
虚拟语气知识体系：
| 条件从句中的谓语动词形式 | 主句中的谓语动词形式 | |
| 与过去事实相反 | had+过去分词 | should/would+have+过去分词 |
| 与现在事实相反 | 过去式 | should/would+动词原形 |
| 与将来事实相反 | 1、过去式 | should/would+动词原形 |
| 2、should+动词原形 | should/would+动词原形 | |
| 3、were to+动词原形 | should/would+动词原形 |
虚拟条件句的倒装：
虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略，再把were, should或had移到从句句首，实行倒装。
如：Were they here now, they could help us.=If they were here now, they could help us.
Had you come earlier, you would have met him=If you had come earlier, you would have met him.
Should it rain, the crops would be saved.=Were it to rain, the crops would be saved.
注意：在虚拟语气的从句中，动词“be”的过去时态一律用“were”，不用was，即在从句中be用were代替。
如：If I were you, I would go to look for him. 如果我是你，就会去找他。
If he were here, everything would be all right. 如果他在这儿，一切都会好的。
典型例题：_____to do the work, I should do it some other day.
A. If were I
B. I were
C. Were I
D. Was I
答案：C. 在虚拟条件状语中如果有were, should, had这三个词，通常将if省略，主语提前，变成were, should, had+主语的形式。
但要注意，在虚拟条件状语从句中，省略连词的倒装形式的句首不能用动词的缩略形式。如我们可说Were I not to do.，而不能说Weren't I to do。
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