主谓一致指谓语动词在人称和数上与主语保持一致。
20.1 单数主语配单数谓语
He likes music.
The book is interesting.20.2 复数主语配复数谓语
They like music.
The books are interesting.20.3 and 连接主语
通常表示复数：
Tom and Jack are friends.但如果表示一个整体概念，谓语可用单数：
Bread and butter is my usual breakfast.
黄油面包是我通常的早餐。20.4 either...or, neither...nor, not only...but also
谓语通常与最近的主语一致，即“就近原则”。
Either you or he is right.
不是你对，就是他对。
Neither he nor his parents are at home.
他和他的父母都不在家。20.5 集合名词
集合名词如果看作整体，谓语用单数；如果强调成员，谓语用复数。
The team is strong.
这个队很强。
The team are discussing their plans.
队员们正在讨论他们的计划。美式英语中集合名词更常作单数，英式英语中更灵活。
20.6 表示时间、距离、金钱、重量等整体概念
常用单数：
Ten years is a long time.
十年是很长一段时间。
Five dollars is enough.
五美元够了。