二、主谓一致(Subject-Verb Concord / Agreement)
主谓一致即句子的主语和谓语在人称和数上保持一致。一般说来，主语的单、复数形式决定着谓语动词应采取的相应形式。在实际应用中，有时情况较为复杂，但在现代英语中基本遵循如下原则：语法一致原则、意义一致原则和就近原则。
语法一致原则
语法一致原则就是根据主语的语法形式决定其谓语动词的语法形式。主语是单数，谓语动词就用单数形式;主语是复数，谓语动词就用复数形式。例如：
A letter has been sent to every student.
Two letters have been sent to every student.
To treat them in that way is unfair.
Smoking cigarettes is dangerous to your health.
意义一致原则
意义一致原则指主谓之间的一致关系不是由主语的语法形式来决定，而是由主语所表达的意义来决定。形式是单数的主语，其谓语可能是复数形式;反之，形式是复数的主语，其谓语有可能是单数。例如：
The class are doing experiment on heat and light.
The team are playing magnificently.
The United States is a country advanced in science and technology.
Ten dollars is all I have left.
Two thirds of the area is under water.
同一单词作主语，根据其表达意义的不同，有时用单数动词，有时却要用复数动词。例如：
The family is the basic unit of the society.
The family have agreed among themselves to spend their vacation in Italy.
就近原则
就近原则是指谓语动词与它最近的名词、代词或其他词在人称或数上保持一致。常见于either … or, neither … nor等并列结构或there, here引起的句子中。例如：
Either you or he was wrong.
There is a pen, a few envelopes and some paper in the drawer.
Not only his children but he himself is hoping to be there.
上述三条原则的具体应用比较复杂，以下几点需要特别注意。我们分三大类情况来看：
1. 谓语动词用单数的情况
1)one, each, every, everyone, everybody, no, no one, one of, many a, either, neither, nobody, anyone, somebody, someone等作主语或主语修饰语时，谓语动词用单数。例如：
Every boy and girl is treated in the same way.
Neither of them drinks coffee.
Each man and (each) woman has good reason to be proud of the work done by their fathers.
2)a kind of, a sort of, a portion of, a section of, a series of, a succession of, a pair of, a couple of等修饰主语时，谓语动词一般根据语法一致原则用单数。例如：
A pair of scissors is what he needs now.
A series of lectures on radio engineering is scheduled.
There is a couple of vacant rooms behind the office.
3)表示国家、单位、书报等名称或表示时间、距离、体积、度量衡(将其视为一整体)等的名词或短语作主语时，谓语动词用单数。例如：
The Netherlands is famous for its tulips.
One hundred miles is too far to travel on foot.
Ten pounds was missing from the bill.
The Thirty-Nine Steps is an interesting novel.
4)不定式、动名词短语或名词性从句作主语时，谓语动词也要用单数。例如：
To master at least a foreign language is very necessary in the present conditions.
Forgetting the past means nothing but betrayal.
When they will start on their journey hasn’t been decided.
5)单数词作主语，虽然后接由including, as well as, together with, in addition to, accompanied by等词或短语连接其他的词，谓语动词仍然用单数。例如：
Gold, as well as silver, ahs recently risen in price.
The factory, with all its equipment, has been burned.
John together with his brother has gone to the party.
2. 谓语动词用复数的情况
1)both, some, few, many, several, the majority (of), the minority (of)等词语作主语或主语修饰语时，谓语动词用复数。例如：
Both of them have gone to Shanghai on business.
Few of my classmates really understand me.
The majority of (the) doctors believe smoking is harmful to health.
2)以复数形式结尾的山脉、群岛、瀑布等专有名词作主语时，谓语动词用复数。例如：
The Niagara Falls are very spectacular.
The Philippines are in the Pacific Ocean.
3)表示群体或类属的“the + 形容词”作主语时，谓语动词用复数。例如：
The injured were sent to hospital at once.
In many western films, the good are well rewarded and the bad are punished.
3. 谓语动词的单、复数要视情形而定的情况
1)由and 连接两个主语时，谓语动词一般用复数。例如：
Your problem and mine are similar.
但当and连接的词语作整体考虑，指同一人、同一事物或概念时，谓语动词用单数。例如：
The worker and poet has published a collection of poems recently.
Too much work and too little rest often leads to illness.
当and连接两个形容词修饰一个单数名词作主语时，如果指一件事物谓语动词用单数;如果指两件事物则谓语动词用复数。例如：
A black and white (黑白相间) horse was trotting down.
The red and the yellow rose are both beautiful.
2)集合名词如family, group, team, the public, crowd, committee, staff等作主语，表整体意义时谓语动词用单数;表个体意义时用复数。例如：
Our team has won the game.
Our team are discussing about how to win.
3)一些表示数量的短语如a lot of, any of, most of, half of, two-thirds of, eighty percent of, part of, the rest of, some of, none of, all of等与名词连用时，后面名词用单数则谓语动词用单数;名词用复数，谓语动词也用复数。例如：
A large percentage of our pilots retire early.
A large percentage of his income is paid in income tax.
Most of the book is interesting.
Most of the books are informative though a little dull.
4)另一些表示数量的短语如a number of, a total of, an average of等后接复数名词，谓语动词用复数;但其中不定冠词换成定冠词时，谓语动词要用单数。例如：
A number of students were late for school owing to the storm.
The number of jobs is increasing.
An average of 3000 letters a month are received by the newspaper’s office.
The average of letters received each month is 3000.
Exercise
1. Directions: Tick out (选出) the correct form of the verb given in the brackets to complete each sentence.
1) There (seem, seems) to be many arguments on both sides.
2) Two-thirds of this (has, have) been finished.
3) Now the band (is, are) putting away their instruments.
4) Ten divided by two (equal, equals) five.
5) A pair of trousers (is, are) on the sofa.
6) The article is one of the best stories that (has, have) ever been written.
7) Neither the teacher nor the students (has, have) enough time.
2. Directions: put the following sentences into English.
1) 各种办法都试过了。
2)来自北方的学生不多。
3)战争与和平是历史永恒的主题。
4)除了两个佣人之外，晚宴没有人迟到。(except)
5)事先起草一篇作文是个好主意。
6)事故是由什么引起的完全是个谜。
7)许多人为了革命事业牺牲了自己的生命。(many a)
8)不但教师反对，学生也反对这一改变。
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