口诀：

单数句子变，变化规则要记住。

名词代词要变化，am, is要变are。

this, that变成啥，these, those来替它。

he, she, it要变啥，全部变they不用怕。

I要变we莫落下，名词后面把s/es加。

名前冠词去掉它，其余成分原样加。

具体注意下面的六要素：

1.单数主格人称代词要变成相应的复数主格人称代词，即I→we; you→you; she, he, it→they。 如： She is a girl.→They are girls.

2. am, is要变为are。 如： I'm a student. →We are students.

3.不定冠词a, an要去掉。如： He is a boy. →They are boys.

4.普通单数名词要变为复数形式。如： It is a cat. →They are cats.

5.指示代词this, that要变为these, those。如： This is a book.→These are books.

6. man, woman作定语修饰可数名词时，要在 "数"上与被修饰名词保持一致。但其他名词修饰名词表示 "性质"时，不作变化。

如：

He is a man doctor.→They are men doctors. This is an apple tree.→They are apple trees. 单复数相互转换，每空一词(含缩写)。

1. The woman is a nurse.(改为复数句)

The _________ _________ _________.

2. There are some old cars.(改为单数句)

There _________ _________ old _________.

3. He has a new book.(改为复数句)

_________ _________ new _________.

4. Are these your chicks ?(改为单数句)

_______ _______ your _______?

5. Is there a sheep in the playground?(改为复数句)

________ there ________ ________ in the playground?