1. 語法一致原則

該原則要求謂語動詞必須與主語在語法形式上保持一致，即主語是單數形式，動詞用單數形式，主語是復數形式，動詞用復數形式：

Both my parents are doctors. 我的父母都是醫生。

The living-room walls are a light yellow. 客廳的墻是淡黃色。

The two factories are in the same locality. 兩家工廠都在同一個地區。

Her job is teaching French. 她的工作是教法語。

The location of the house is near the highway. 房子的地點靠近公路。

A large amount of damage was done in a short time. 短期內造成大量損害。

2. 意義一致原則

有時候謂語動詞的數取決于主語所表示的概念，而不是其語法形式：

This news is important for us. 這條消息對我們很重要。

Paris is among the largest cities in the would. 巴黎是世界上最大的城市之一。

The thesis was about a hundred and fifty pages long. 論文有一百五十頁長。

Watch out! The police are coming. 當心，警察來了。

Less people are going to university than usual. 現在上大學的人比平時少。

3. 就近原則

有時，謂語動詞的數決定于主語中最靠近它的詞語：

Either you or I am wrong. 不是你錯了就是我錯了。

Neither the students nor the teacher is interested in it. 老師和學生對此都不感興趣。