变为复数形式

题目

变为复数形式
It's a knife
He is an English teacher
I'm a student
就换线部分提问
Thses are (Aaerican cars 划线)
The apples are (on the three 划线）
That boy is (Paul划线）

答案

they are knives
they are english teachers
we are students
what are these
where are the apples
who is the boy