This is a boy and a girl.为什么不说these are a boy and a girl.

This is a boy and a girl.为什么不说these are a boy and a girl.
This is a boy and a girl.为什么不说these are a boy and a girl.

This is a boy and a girl.为什么不说these are a boy and a girl.
This is a boy.
This is a girl.
This is a boy and a girl.
是分开来的.除非不是一起说的,就像
These are the girls.
These are the boys.
These are the children.