英语句子中，大部分主语都是名词。名词的单复数形式(或含义)直接影响着谓语动词的形式，也就是说，谓语动词的单复数形式要和主语保持一致。这种谓语在人称和数方面与主语的一致就叫作主谓一致。主谓一致有三个原则：语法一致原则，意义一致原则及就近一些原则。
一、主谓一致的三个原则
(一)语法一致原则
语法一致原则是指谓语动词要和它的主语在语法形式上取得一致，即单数主语用单数动词，复数主语用复数动词。如：
China is a big country with a long history.中国是一个历史悠久的大国。
These books are all Wei Fang's. 这些书都是魏芳的。
[特别提醒]
谓语动词的单复数不受主语修饰的影响。如：
The building among the trees is our public library.树丛中的房子是我们的公共图书馆。(among the trees是介词短语，修饰主语the building；尽管修饰语中有复数名词trees，但其不影响谓语动词的单数形式。)
The questions raised by Mr Wang are of great importance. 王先生提出的问题很重要.(raised by Mr Wang是过去分词短语，修饰主语the questions；尽管修饰语中有单数名词Mr Wang，但其不影响谓语动词的复数形式。)
(二)意义一致原则
意义一致原则是说谓语动词的单复数要取决于主语表达的意义，而不是形式。如：
The news is inspiring.这消息令人鼓舞。
People are talking about the news.人们在谈论这条消息。
(三)就近一致原则
就近一致原则是指谓语动词的数要与它最邻近的名词的数保持一致。如：
Either you or the headmaster is to hand out the prizes to these gifted students at the meeting.要么你，要么校长，将在大会上为这些有才华的学生颁奖。
--Are both Ann and I going to the party? 我和安都去参加聚会吗？
--No, neither you nor Ann is going. 不，你们谁也不去。
Not only the teacher but also his students like playing football.不仅这位老师喜欢踢足球，而且他的学生们也都喜欢踢足球。
二、主谓一致的几种情况
(一)复数形式主语用单数动词的情况
[典型例题]
用所给词的适当形式填空。
1.The Arabian Nights ____(be) an interesting story book.
2.Physics ____(be) a subject that every student should learn in middle school.
3.Thirty dollars ____(be) too expensive for this dictionary.
4.As you can see, the number of cars on our roads ____ rising these days.
A.was keeping B.keep C.keeps D.were keeping
5.With more forests being destroyed, huge quantities of good earth ____ each year.
A.is washing away B.is being washed away
C.are washing away D.are being washed away
[试题解析及语法归纳]
1.is。表示国家、城市、人名、书名、报纸、杂志及组织等专有名词作主语时，通常作为整体看待，谓语动词用单数。如：
The United States lies in North America.美国位于北美洲。
The New York Times is read all over the United States.《纽约时报》是流行于美国各地的报纸。
2.is。以-ics结尾表示学科名称的名词作主语时，谓语动词用单数，这类名词有：physics, mathematics等；另外，以-s结尾的名词：nwes, plastics等，也同属此类。如：
Politics is now taught in all schools.现在各个学校都开设政治课。
Plastics is a kind of matter.塑料是一种物质。
3.is。表示时间、距离、金钱、重量、度量、容量、温度等复数名词作主语时，通常看作一个整体，谓语动词用单数。如：
Twenty-five thousand dollars is the average income for a four-person family living in a mediumsized community in the United States.两万五千美元是一个居住在美国中等社区四口之家的平均收入。
Two hours is not long enough for this work.对做这项工作来说，两个小时不算长。
[特别提醒]
如果说话人侧重于一个个的个体时，谓语动词可以用复数。如：
Thirty years have passed since he left home.自从他离开家以后，三十年已经过去了。
4.C。车辆的数量在不断地增长，这是事实，所以用一般现在时。“the number of+复数名词或代词”作主语时，表示“……的数量”，谓语动词用单数。如：
The number of people who own cars is increasing every year.拥有汽车的人数每年在增加。
而“a number of+名词复数”作主语时，表示“许多……”，谓语动词用复数。如：
A number of people have cars now.现在许多人都拥有汽车。
5.D。本句主语是复数形式，故谓语应用复数形式。(large)quantities of修饰复数可数名词以及不可数名词作主语时，谓语动词一般用复数；a (large) quantity of修饰不可数名词作主语时，谓语动词一般用单数；large amounts of修饰不可数名词作主语时，谓语动词一般用复数；a large amount of修饰不可数名词作主语时，谓语动词一般用单数。如：
A large quantity of water is needed for cooling purposes.=Large quantities of water are needed for cooling purposes.冷却需要大量的水。
[帮你归纳]
其他几种复数形式主语用单数动词的情况：
(1)引号中的词若作为整体看待时，谓语动词用单数。如：
“Bikes”is the plural of“bike”“Bikes”是“bike”的复数形式。
“They”is a pronoun.“They”是代词。
(2)一些由两个对应部分组成一体的复数名词(如：trousers, glasses, shoes等)的前面若有“一条，一幅，一把”之类的量词时，谓语动词复数形式应与这些量词的数保持一致。如：
This pair of trousers is his brother's.这条裤子是他哥哥的。
The two pairs of trousers are his brother's.这两条裤子是他哥哥析。
(二)单数形式主语用复数动词的情况
[典型例题]
用所给词的适当形式填空。
1.The cattle ____(be) eating grass on the other side of the hill.
2.The Japanese ____(do) the same even now.
3.The wounded ____(be) sent to hospital at once.
[试题解析及语法归纳]
1.are。有些集合名词(如：people, police, cattle等)虽然形式上是单数，但意义上却为复数，谓语动词需用复数形式。如：
The police are searching for a thief.警察正在搜捕一名小偷。
What are those people? 那些人是干什么的？
2.do。有些以-sh，-ese，-ch，-iss结尾的表示国家、民族的形容词与定冠词the连用时，指整个民族，表示复数含义，谓语动词用复数。如：
The Chinese are kind and friendly.中国人亲切、友好。
Chinese is difficult language.汉语是一种很难的语言。
3.were/was。某些形容词加上定冠词the(如：the old, the young, the dead, the rich, the sick等)时，用来表示一类人，其意义为复数，谓语动词用复数形式。如：
The old are taken good care of in our country.在我们国家老人受到很好的照顾。
The rich are for the plan, but the poor are againstit.富人赞成这个计划，但穷人反对。
但是，如果这些词表示抽象概括或指个人时，谓语动词仍用单数。如：
The wounded was taken to a hospital.这个伤员被送到了医院。
The beautiful is not always the same as the good.漂亮的不一定就是好的。
(三)同是单数形式主语，动词形式不同的情况
[典型例题]
用所给词的适当形式填空。
1.Class 6 ____(be) playing football on the playground.
2.The rest of the story ____(need) no telling.
3.Here ____(be) some books for you.
4.The company had about 20 notebook computers but only one-third ____ used regularly. Now we have 60 working all day long.
A.is B.are C.was D.were
[试题解析及语法归纳]
1.are。有些集合名词(如：family, class, group, team, enemy, government, nation, couple, public等)若作为一个整体看待时，谓语动词用单数；如果就其中一个个成员考虑时，谓语动词则用复数。如：
My family is a large one.我家是个大家庭。
My family are all workers.我的一家人都是工人。
The government has managed to control SARS and bird flu.政府已设法控制了非典和禽流感。
2.needs。“the rest of, a lot of, lots of, plenty of等+名词”作主语时，谓语的数依据名词的数而定。如：
A lot of students are waiting outside.许多学生在外面等候。
Lots of food is needed.需要许多食物。
3.are。在here和there的倒装句中，如主语是复数名词，谓语动词用复数；如主语是单数名词，谓语动词用单数。如：
There are hundreds of people in the hall.大厅里有几百人。
Here is your key.这就是你那把钥匙。
在这种结构中，如果是并列主语时，谓语动词的数常与最近的平行主语相一致。如：
There is a table and some chairs in the room.房间里有一张桌子和一些椅子。
There are some chairs and a table in the room.房间里有一些椅子和一张桌子。
4.D。“分数/百分数+of+名词”作主语时，谓语动词和名词的数保持一致。此句中的分数one-third后省略了of 20 notebook computers。
另外，“some, all, any, none, more, most等+of+名词”作主语时，谓语动词也应与名词的数保持一致。如：
Most of his spare time was spent in reading.他的大部分业余时间都花在读书上。
Most of his books were lost.他的大部分书都丢了。
More than 70 percent of the surface of our planet is covered by water.我们这颗行星70%多的表面被水覆盖。
One-third of the students are girls in our group. 我们组三分之一的学生是女生。
(四)并列主语与谓语动词的一致关系
[典型例题]
1.The father as well as his three children ____ skating on the frozen river every Sunday afternoon in winter.
A.is going B.go C.goes D.are going
2.The teacher, with 6 girls and 8 boys of her class, ____ visiting a museum when the earthquake struck.
A.was B.were C.had been D.would be
用所给词的适当形式填空。
3.What he said and what he did ____(have) greatly encouraged the other students.
4.Neither his parents nor his wife ____(be) at home.
[试题解析及语法归纳]
1.C。as well as连接名词或代词作主语时，遵循就近原则；另外，句中时间为every Sunday afternoon in winter，故为一般现在时。
2.A。由with连接两个主语时，谓语动词应与with前的主语保持一致；另外，根据句意可知，要用过去进行时态。
由as well as, with, but, besides, except, like, including, along with, together with等连接两个并列主语时，谓语动词的数取决于前一个主语。如：
A library with twenty thousand books has been offered to the college as a gift.一个拥有两万藏书的图书馆被作为一个礼物捐给这所大学。
The teacher as well as the students likes the painting.老师和学生们都喜欢这幅画。
3.have。由and或both…and连接的两个单数主语，表示两个不同的人或物，意义上为复数，谓语动词需用复数形式。如：
Both my father and my sister are teachers.我爸爸和姐姐都是老师。
Fire and water do not agree.水火不相容。
[特别提醒]
在下列情况，谓语动词需用单数形式：
(1)由and连接的两个单数主语，指同一人、同一物或同一概念时，谓语动词用单数。如：
The teacher and writer has come to the meeting.那位老师兼作家来开会了。
(2)由and连接的两个单数主语，如果其前面有every, each, no等词修饰时，谓语动词用单数。如：
Every boy and every girl has the right to be educated.每个男孩和女孩都有受教育的权利。
(3)有时用and连接两个单数主语时，谓语动词既可以是单数，也可以是复数。如：
Five and four makes/make nine.五加四等于九。
4.is。由or, either…or, nor, neither…nor, not only…but also等连接两个并列主语时，谓语动词的数一般与后一个主语的数相一致。如：
Either you or I am to do the work.或者是你，或者是我做这个工作。
(五)几种特殊结构的主谓一致
[典型例题]
1.He is the only one of the students who ____ a winner of scholarship for three years.
A.is B.are C.have been D.has been
用所给词的适当形式填空。
2.A day or two ____(have) passed.
3.More than one soldier ____(be)killed in the battle.
4.Many a ship ____(have) been damaged in the storm.
5.One and a half hours ____(have) passed, but he hasn't come here.
6.Each of us ____(have) a dictionary.
7.I, not you, ____(be) the right person to do the work.
8.Walking on the moon ____(be) very difficult.
9.In front of the house ____(be) some flowers.
[试题解析及语法归纳]
1.D。the only one of the students中的先行词是one，故定语从句中的谓语动词要用单数；又因for three years是完成时的标志，所以答案为D。
在“one of+复数名词+定语从句”结构中，定语从句一般被看作是修饰复数名词，因此该从句中的谓语动词要用复数；但是在“the only one of+复数名词+定语从句”结构中，先行词是one而不是靠近它的复数名词，因此该从句的谓语动词应该是单数形式。如：
This is one of the best movies that have been on this year.这是今年上映的最佳影片之一。
She was the only one of the girls who was late for the meeting.她是这些女孩中开会唯一迟到的一个。
2.has。“a+单数名词+or two”作主语时，谓语动词用单数；但是当“one or two+复数名词”作主语时，谓语动词用复数。如：
One or two days have passed.一两天已经过去了。
3.was。“more than one+单数名词”结构虽有复数意义，但谓语动词习惯上用单数形式。如：
More than one student has read Rowling's Harry Porter.许多学生都看过罗琳的《哈利·波特》。
4.has。“many a+单数名词”作主语时，尽管意义上是复数，但谓语动词常用单数形式。如：
Many a student has seen the film Titanic twice.许多学生都看过两次电影《泰坦尼克号》。
5.has。“one and a half+复数名词”作主语时，谓语动词用单数。如：
One and a half apples is left on the table.一个半苹果剩在桌子上。
6.has。由each或each修饰名词作主语时，谓语动词用单数；但是，如果each位于复数主语后或在句末作主语的同位语时，不影响谓语动词的数，谓语动词仍用复数形式。如：
Each student has made a mistabke.每个学生都犯过错误。
The students each have a new book.学生们人手一册新书。
7.am。当两个主语中一个为肯定，另一个否定时，谓语动词的数与肯定主语相一致。如：
She, not you is geing to the shop.她，不是你去商店。
8.is。动词-ing形式、不定式或从句作主语时，谓语动词用单数。如：
To talk with him is a great pleasure.和他谈话是一件愉快的事。
What he said is right.他说的是对的。
[特别提醒]
如两个或两个以上的动名词、不定式或从句作主语时，谓语动词用复数。如：
What to do and how to do heven't been decided.做什么，怎样做还没有决定。
9.are。在倒装结构中，谓语的数应与其后主语的数相一致。如：
At the foot of the mountain stands a tall building.山脚下有一幢高楼。
