事实上，She doesn’t know, so she still feels joyous.)
二、对过去事实的虚拟
基本形式：If + had done…, …would /could / should /might + have done
例如：If she had been warned earlier, she wouldn’t have broken the rules.
(事实上：She was not warned earlier and she broke the rules.)
If it hadn’t rained, the match would have seemed more fascinating.
(事实上：It rained and the match was less fascinating.)
此种虚拟可进行倒装，如：
Had the letter been sent out, it would have ruined our friendship.= If the letter had been sent out,
it would have ruined our friendship.
三、对将来事实的虚拟基本形式：
If + should do…, …would /could /should /might + do; 意思类似汉语中的“万一”
例如：If he should forget the date, I might teach him a good lesson.
(事实上：他不大可能忘记那个日期)
If it should snow this afternoon, we could make a snowman.
(事实上不大可能会下雪)
此种虚拟可倒装，如：Should my car fail, I would have to return home on foot.= If my car should fail,
I would have to return home on foot.
注意1：部分动词的宾语从句中需用虚拟语气，形式为should do, 其中should常被省略。
此类动词有：insist, demand, suggest, propose, order, require, decide,ask, request等.
例句： We all insist that we (should) not rest until we finish the work.
The professor suggests that the students (should) collect enough mate rials before they work on this project.
上面的动词如果以名词形式出现时，后面的that从句仍然要采用虚拟语气
He gives me the suggestion that I (should) eat breakfast every moning.
注意2：在一些惯用语之后经常需要用虚拟，来表示与事实相反或者难以实现的事情这类习语有： as if , as though, but for, otherwise, without, wish, if only等
例句： But for your help, I would not have arrived here in time.
(如果没有你的帮助，我就不能准时到达)
Without your help, I would not arrive here in time.
注意3：在下列形容词引导的that从句中必须要用虚拟语气(should) do，但是由于 should经常被省略，所以实际上用的就是动词原形。
这类形容词有: It is important/ necessary/ proper/ imperative/ essential/advisable等 + that
例句：It is necessary that he (should) realize his situation.
一致原则
一致原则贯穿英语语法，在前面各个章节中已有涉及，本章作为对前面的补充，集中讲、TOEFL题中常考的问题
第一节 主谓一致
主谓一致指的是主语和谓语在数上要保持一致. 在英语除了时态的变化外，名词、动词的数也有差别，这就要求主语(以名词为代表)和谓语(包括助动词)在数上要一致如：
1. 在名词+of+名词这种结构中, 前一个名词是整个短语的中心词, 当该短语作主语时，一般以of之前名词的数为依据确定谓语的数.one of 之后需接复数名词，但one of+名词作主语时中心词是one，故谓语应用单数 One of my students wins the game.
2. 由and连接的多个名词作主语，谓语动词应用复数
Career and love are important to me.
im, John and Mary are playing football.
但是如果用and连接起来表示单一的概念时，谓语动词要用单数
The famous singer and actress, Whitney Huston is coming to the ceremony.
(在这里, singer和actress指得是同一人, 都是Whitney Huston)
3. 不可数名词，尤其是抽象名词(relation, authority, necessity, power, democr acy, young等)作主语时要视为单数，谓语自然也要用单数
The relation between us is very simple.
4. 单个从句作主语时，谓语用单数
That she has gone insane is sheer rumor.
When they will come hasn’t been made public.
5. 如果主语是单数，那么即使后面有
with/ together with/ alongwith/accompaniedby, no less than, like, but, except, including, besides
等引导的短语，谓语动词仍然要是用单数
例如：The boy, together with his parents, goes to the cinema today.
No one except the two boys knows how to solve this problem.
6. 由Not A but B, Not only A but also B, either A or B, neither A nor B引导的主语，谓语通常和最邻近的主语相一致
Either you or Mary hurts her.
Neither my wife nor I myself am able to persuade my daughter to change her mind.
Not you but he is tired of typing.
Not only the students but also the teacher is going to be blamed.
7.在there be句型、介词短语、副词为句首引起的倒装句中，真正的主语通常在谓 语的后面，谓语应该和后面的主语在数方面相一致。
但是在there be 句型中，如果有两个或者两个以上的主语，必须和最接近他的那个主语相一致。
There are a lot of books on the table.
There is only one pencil, two books and one cup on the table.
Many a time has he given us good advice.
第二节 主从句时态一致
主从句语义相互关联，时态也需呼应，所谓一致并不是说主从句的时态要一模一样，而是不能脱节，一般的原则是不能跨越大的时间范畴，如：主句是一般过去时，从句可能是过去完成时或过去将来时，而不大可能是现在时或将来时，当然具体情况还应具体分析，但针对解答TOEFL题而言，掌握上述原则已是绰绰有余
1.通常当主句中的时态是现在时或将来时态时，从句中的动词时态并不受影响，往往还是根据从句的意思而定。
I know that he will come tomorrow.
I know that he has finished reading this book.
I know that he went to school yesterday.
2. 当主句中的时态是过去时态,那么从句中的时态要作一定的变化
I knew that he would come tomorrow. (现在将来时变为了过去完成时)
I knew that he had finished reading this book. (现在完成时过去完成时)
I was told that he was free today. (现在时态变为过去时态)
第三节 代词与其先行词一致
在讲代词一章时已提到代词的作用是替代已出现过的词，即先行词，那么代词和先行词 之间也应保持性、数的一致才能保证替代的忠实性，不引起误解在改错题中，确定代词的先行词是解题的关键，主要是依靠句意来判断，还需留意下列情况：
1. 反身代词需和所在主谓结构的主语一致，若不一致应改为宾格形式
如：Her mother helped her solve the problem.
此句中helped之后若用herself则指的是her mother, 语义不同
2. 在主从句中，或有分词状语的句子中，代词所代替的对象有可能在其后出现，要准确识别
如：After she entered the room, Mary flung herself to the bed. 此句中she指代的是主句中的Mary
二、对过去事实的虚拟
基本形式：If + had done…, …would /could / should /might + have done
例如：If she had been warned earlier, she wouldn’t have broken the rules.
(事实上：She was not warned earlier and she broke the rules.)
If it hadn’t rained, the match would have seemed more fascinating.
(事实上：It rained and the match was less fascinating.)
此种虚拟可进行倒装，如：
Had the letter been sent out, it would have ruined our friendship.= If the letter had been sent out,
it would have ruined our friendship.
三、对将来事实的虚拟基本形式：
If + should do…, …would /could /should /might + do; 意思类似汉语中的“万一”
例如：If he should forget the date, I might teach him a good lesson.
(事实上：他不大可能忘记那个日期)
If it should snow this afternoon, we could make a snowman.
(事实上不大可能会下雪)
此种虚拟可倒装，如：Should my car fail, I would have to return home on foot.= If my car should fail,
I would have to return home on foot.
注意1：部分动词的宾语从句中需用虚拟语气，形式为should do, 其中should常被省略。
此类动词有：insist, demand, suggest, propose, order, require, decide,ask, request等.
例句： We all insist that we (should) not rest until we finish the work.
The professor suggests that the students (should) collect enough mate rials before they work on this project.
上面的动词如果以名词形式出现时，后面的that从句仍然要采用虚拟语气
He gives me the suggestion that I (should) eat breakfast every moning.
注意2：在一些惯用语之后经常需要用虚拟，来表示与事实相反或者难以实现的事情这类习语有： as if , as though, but for, otherwise, without, wish, if only等
例句： But for your help, I would not have arrived here in time.
(如果没有你的帮助，我就不能准时到达)
Without your help, I would not arrive here in time.
注意3：在下列形容词引导的that从句中必须要用虚拟语气(should) do，但是由于 should经常被省略，所以实际上用的就是动词原形。
这类形容词有: It is important/ necessary/ proper/ imperative/ essential/advisable等 + that
例句：It is necessary that he (should) realize his situation.
一致原则
一致原则贯穿英语语法，在前面各个章节中已有涉及，本章作为对前面的补充，集中讲、TOEFL题中常考的问题
第一节 主谓一致
主谓一致指的是主语和谓语在数上要保持一致. 在英语除了时态的变化外，名词、动词的数也有差别，这就要求主语(以名词为代表)和谓语(包括助动词)在数上要一致如：
1. 在名词+of+名词这种结构中, 前一个名词是整个短语的中心词, 当该短语作主语时，一般以of之前名词的数为依据确定谓语的数.one of 之后需接复数名词，但one of+名词作主语时中心词是one，故谓语应用单数 One of my students wins the game.
2. 由and连接的多个名词作主语，谓语动词应用复数
Career and love are important to me.
im, John and Mary are playing football.
但是如果用and连接起来表示单一的概念时，谓语动词要用单数
The famous singer and actress, Whitney Huston is coming to the ceremony.
(在这里, singer和actress指得是同一人, 都是Whitney Huston)
3. 不可数名词，尤其是抽象名词(relation, authority, necessity, power, democr acy, young等)作主语时要视为单数，谓语自然也要用单数
The relation between us is very simple.
4. 单个从句作主语时，谓语用单数
That she has gone insane is sheer rumor.
When they will come hasn’t been made public.
5. 如果主语是单数，那么即使后面有
with/ together with/ alongwith/accompaniedby, no less than, like, but, except, including, besides
等引导的短语，谓语动词仍然要是用单数
例如：The boy, together with his parents, goes to the cinema today.
No one except the two boys knows how to solve this problem.
6. 由Not A but B, Not only A but also B, either A or B, neither A nor B引导的主语，谓语通常和最邻近的主语相一致
Either you or Mary hurts her.
Neither my wife nor I myself am able to persuade my daughter to change her mind.
Not you but he is tired of typing.
Not only the students but also the teacher is going to be blamed.
7.在there be句型、介词短语、副词为句首引起的倒装句中，真正的主语通常在谓 语的后面，谓语应该和后面的主语在数方面相一致。
但是在there be 句型中，如果有两个或者两个以上的主语，必须和最接近他的那个主语相一致。
There are a lot of books on the table.
There is only one pencil, two books and one cup on the table.
Many a time has he given us good advice.
第二节 主从句时态一致
主从句语义相互关联，时态也需呼应，所谓一致并不是说主从句的时态要一模一样，而是不能脱节，一般的原则是不能跨越大的时间范畴，如：主句是一般过去时，从句可能是过去完成时或过去将来时，而不大可能是现在时或将来时，当然具体情况还应具体分析，但针对解答TOEFL题而言，掌握上述原则已是绰绰有余
1.通常当主句中的时态是现在时或将来时态时，从句中的动词时态并不受影响，往往还是根据从句的意思而定。
I know that he will come tomorrow.
I know that he has finished reading this book.
I know that he went to school yesterday.
2. 当主句中的时态是过去时态,那么从句中的时态要作一定的变化
I knew that he would come tomorrow. (现在将来时变为了过去完成时)
I knew that he had finished reading this book. (现在完成时过去完成时)
I was told that he was free today. (现在时态变为过去时态)
第三节 代词与其先行词一致
在讲代词一章时已提到代词的作用是替代已出现过的词，即先行词，那么代词和先行词 之间也应保持性、数的一致才能保证替代的忠实性，不引起误解在改错题中，确定代词的先行词是解题的关键，主要是依靠句意来判断，还需留意下列情况：
1. 反身代词需和所在主谓结构的主语一致，若不一致应改为宾格形式
如：Her mother helped her solve the problem.
此句中helped之后若用herself则指的是her mother, 语义不同
2. 在主从句中，或有分词状语的句子中，代词所代替的对象有可能在其后出现，要准确识别
如：After she entered the room, Mary flung herself to the bed. 此句中she指代的是主句中的Mary
