句子的核心是谓语动词，谓语动词的确定取决于主语。
根据句子含义和结构认准主语是掌握主谓一致的必要条件；弄清主谓一致的语言规则和习惯是掌握主谓一致的充分条件，要正确使用主谓一致，两个条件缺一不可，但同学们往往会走入以下三大误区。
误区一 误认主语
1. 倒装句
①Between the two buildings are a big tree. （×）
②Between the two buildings is a big tree. （√）
【解析】 第①句谓语动词使用are，错误地认为the two buildings是该句的主语，但实际上是介词between的宾语，一起构成介词短语，而介词短语不能充当主语。该句是一个倒装句，真正主语是a big tree。因此第②句正确。
特别提醒 倒装句的常见结构：副词/介词短语+谓语+主语
2. 主语之后带有介词短语
①The fruit like apples , oranges are good for our health. （×）
②The fruit like apples , oranges is good for our health. （√）
【解析】 第①句误认为apples , oranges是主语，因此谓语动词用are，而实际上the fruit才是该句的主语，like apples , oranges是介词短语作后置定语修饰the fruit。该句译为“像苹果、桔子之类的水果对我们的身体是有好处的”。因此第②句是正确的。
特别提醒 类似的结构有：主语+with / like / except / but / together with / as well as . . . ，谓语动词应与主语一致，而与介词短语之后的名词无关。
3. one of . . . + 名词复数或复数代词
①There are twenty boys in our class. One of the boys are from Canada. （×）
②There are twenty boys in our class. One of the boys is from Canada. （√）
【解析】 one of the boys的中心词是one，因此谓语动词用单数，造成第①句错误的原因主要是把the boys当成了该句的主语。
4. 定语从句
①I like the photos which was taken in Beijing. （×）
②I like the photos which were taken in Beijing. （√）
【解析】 which were taken in Beijing是一个定语从句，用于修饰先行词the photos，而which本身就代替先行词the photos。因此谓语动词要用复数，造成第①句错误的原因是没有弄清楚关系词which的实质，只是从形式上看它是单数。
特别提醒 定语从句中的谓语动词应该与先行词保持一致。
误区二 被主语的表象迷惑
1. 看似复数却表单数概念
①Maths are my favourite subject. （×）
②Maths is my favourite subject. （√）
【解析】 maths本身是一个以“s”结尾的单词，而不是一个复数名词，表示单数概念“数学”这一学科，因此第②句正确。
类似的有：physics , news , politics . .
.
2. 看似单数却表复数概念
①The police is searching for the robbers. （×）
②The police are searching for the robbers. （√）
【解析】 the police译为“警方”，表示复数概念，而不是表示“那个警察”，因此第②句正确，类似的词有：people , the + 形容词，the + 姓 + family等均表复数概念。
3. 名词的单复数同形
①There are a little sheep eating grass on the hill. Can you see it? （×）
②There is a little sheep eating grass on the hill. Can you see it? （√）
【解析】 sheep是一个单复数形式相同的名词，由于sheep之前用的a little修饰，加上Can you see it中的it指代单数，因此a little sheep译为“一只小绵羊”，因此第②句正确。如果将原题改为：There ________ （be） a few sheep eating grass on the hill. Can you see them?那又会怎么样呢。
特别提醒 类似的单复数形式相同的词还有fish, Chinese, Japanese等，要根据句子的含义和结构暗示来判断其单复数。
4. 集合名词
①Their family is very happy. Now their family is watching TV. （×）
②Their family is very happy. Now their family are watching TV. （√）
【解析】 family是一个集合名词，表示整体概念时谓语用单数，表示个体概念时谓语用复数。该句译为“他们全家很幸福，现在全家人正在看电视”。因此第一个family表示整体概念，译为“家庭”，第二个family表示个体概念，译为“家人”，第②句正确。
特别提醒 类似的还有group, class, team等既可表单数也可表复数。
误区三 误用语言规则
1. 表示时间、距离、金钱、重量、数量等名词作主语
①Ten years are quite a long time. （×）
②Ten years is quite a long time. （√）
【解析】 表示时间、距离、金钱、重量、数量等名词的复数作主语时看作一个整体，谓语动词要用单数，容易错误理解为复数而出现第①句的错误。
2. 由and连接的并列主语
①The twentieth lesson and last lesson are very easy for students. （×）
②The twentieth lesson and last lesson is very easy for students. （√）
【解析】 the twentieth lesson and last lesson是表示同一概念，译为“第20课即最后一课”，因此谓语动词应该用单数。同学们容易错误理解“第20课和最后一课”，如果表示两课，应该表达为“the twentieth lesson and the last lesson”。
特别提醒 由and连接的并列主语表示同一概念时，谓语动词用单数，表示不同的概念时谓语动词用复数。
3. 就近原则
①Neither you nor he have been to Beijing. （×）
②Neither you nor he has been to Beijing. （√）
【解析】 neither . . . nor连接的并列主语（you , he）虽然表示两个人，但根据语言规则，当它连接并列主语的时候，谓语动词根据就近原则，该由he决定，因此第②句正确。
特别提醒 类似的还有either . . . or, not only . . . but also, not . . . but, 以及there be之后的并列主语，谓语动词的确定都根据“就近原则”。
4. this kind of, a piece of, this pair of等短语作主语
①This pair of trousers are very new, but Tom’s trousers are very old. （×）
②This pair of trousers is very new, but Tom’s trousers are very old. （√）
【解析】 trousers作主语时，谓语动词用复数，但当它被this pair of修饰时谓语动词由pair的单复数确定。因此第②句正确。
特别提醒 this kind of, a piece of, a bag of, a box of等，这类短语作主语时谓语动词的单复数由这些短语中的名词决定，而与它们所修饰的名词无关。
5. the rest of，half of等短语作主语
①Half of the students have finished most of the work. The rest of it are very difficult. （×）
②Half of the students have finished most of the work. The rest of it is very difficult. （√）
【解析】 根据句意和句子结构可以判断the rest of it中的it，指the work，而work是不可数名词，因此第②句正确。
特别提醒 all of, most of, half of, the rest of，以及a lot of, some, any+名词作主语时，要根据后面的名词确定谓语动词的单复数。
6. 一句话提示
①合成不定代词（如something，anybody等）作主语，谓语动词用单数；
②动名词、不定式、从句作主语时，谓语动词用单数；
③a number of + 名词（复）作主语，谓语用复数，the number of + 名词（复）作主语，谓语用单数；
④none of . . . 作主语时，谓语动词可用单数，也可用复数。
以下是总结的几个经典题目
拿来好好练习
根据句意，从所给出的选项中选出最佳答案。
1. The news _____ very worth listening to.
A. be B. is C. are D. am
2. —_____ this pair of glasses yours?
—No. My glasses _____ on the desk.
A. Is, is B. Are, is C. Is, are D. Are, are
3. The old _____ taken good care of in China now.
A. was B. are C. is D. were
4. Nobody except the twins ___ to Hongkong before.
A. have been B. have gone C. has been D. has gone
5. —What’s on the plate?
—There _____ some rice on it.
A. is B. are C. has D. have
6. Five years _____ since we met last.
A. have passed B. has past C. has passed D. have pasted
7. Here _____ some flowers for you.
A. is B. are C. has D. have
8. There __________ a number of teachers, but the number of women teachers ________ only thirty.
A. are, are B. are, is C. is, are D. is, is
9. Not only my uncle but also my parents _______ I am right.
A. think B. thank C. thinks D. are thinking
10. Doing morning exercises _____ good for our health.
A. be B. are C. is D. am
11. Everyone likes people who _____ ready to help others.
A. is B. are C. being D. was
12. The Smith family _____ making dumplings in the kitchen.
A. is B. are C. has been D. can
13. One third of the population in our city ______ farmers in the past.
A. are B. were C. is D. was
14. The headmaster and the teacher ______ coming to us now.
A. are B. is C. will D. am
15. Tom as well as his friends _____ skating every Saturday.
A. are B. is C. go D. goes
Keys： 1. B 2. C 3. B 4. C 5. A
6. C 7. B 8. B 9. A 10. C
11. B 12. B 13. B 14. A 15. D
