英语中什麼时候该加s（不只是复数,比如第三人称单数）?

Question

英语中什麼时候该加s（不只是复数,比如第三人称单数）?

Answer 1

一般现在时中,主语为单数第三人称（he, she, it,表第三人称的名词）时,谓语动词不是be动词、没有情态动词及助动词,而是实义动词(有实际意义)要加s.
He has a brother.
She eats an apple every morning.
My father usually walks to his office.
2. 大多数名词变复数时加s, boys, lakes. 少数加es, potatoes. 还有部分不规则变化sheep,deer.