2018考博英语必会语法知识点：主谓一致
2018考博英语复习初期，夯实基础是首要任务，作为英语最基础的知识就是语法，新东方在线考博英语频道整理了一系列考博英语必会语法知识点供考生们参考复习。
这类考题灵活性大，需要根据实际情况判断谓语动词的单复数形式。一部分具有生命意义的集合名词做主语时谓语动词多采用复数形式，如people, poultry, militia等;用and连接的成分表单一概念时谓语动词用单数;就近原则：主语中含有某些连词(如as well as, besides, in addition to等)时，谓语动词的数同第一个主语保持一致。
主谓一致
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.