Question

there is there are怎么用，与they are的区别

Answer 1

There is 后加单数名词或不可数名词
单数There is a book.
不可数名词There is some bread(面包)There are 加复数名词
复数名词There are many trees

追答

There are 和 There is 都属于There be 结构。

Answer 2

1 there be 表示有、存在的含义。其中be可进行单复数变化，there is 后面跟单数可数名词或者不可数名词，there are 后面跟复数可数名词。
There is an apple tree in our school.
There is some water in the cup.
There are many people in the park.
2 They are 他(她、它)们是.......
They are very good children.