英语的基本知识

This is my backpack.
把它变成负数（近的）的话就要变成
These are my backpack.
如果是东西远的时候
Those are my backpack.
This变成These
或This变成Those
be动词is变成are
时态问题 一般现在 一般过去 一般将来
主+系+表
it
he
she
三个词后加
is name sb.
its
his
her
后加
name is sb.
………………