已经讲过，单数名词加上“s”可以构成复数名词的形式，下面我们来讲讲复数名词的构成方法。
1 加 s
a cap---caps a book----books a dog-----dogs a desk----desks a chair----chairs
2 加 es
a fox---foxes a glass----glasses a watch----watches
3 变词尾fe为ve后加s
a knife-----knives a wife----wives
4 变a为e
a man----men a woman----women
5不规则变化
a tooth----teeth a child----children a mouse---mice
例句：1 I see a man and a woman。
2 Can you see a child？
3 There are men and women in the room。
4 They are men,women and children.
5 I see six balls on the table。