there are和they are的区别是什么?他们有什么区别?分别在什么情况下用?请回答时尽可能详细,并有1-3个例子说明.我不是这个意思的，我是问。给你们两个例句吧：What are these？They are apples.What are these？There are legs.是问在这样的句型里有什么区别？

there are 是”有”，they are 是”他们是”

there are 表示“有"
There are some books on the desk.桌上有一些书
There are two apples in the tree.树上有两个苹果。
There are too many people in the room.房间里有太多的人。
而they are 表示"他们是"
They are students. 他们是学生。
They are books. 它们是书。
They are apples.它们是苹果。

there are 有
There are a lot of books on the desk.
桌子上有很多书.
There are a few chalks in the box.
盒子里有一些粉笔.
they are 他们(是)...
They are students.
他们是学生.
They are ready to help others.
他们乐于主人

There are 表示数目有多少
They are表示 他们（它们）是...............

there are 是表示有.是there be 句型
they are 是 表示 他们是
完全不同的!
比如
There are many boys running in the playground.
操场上有很多男生在跑步
They are boys,not girls.
他们是男生,不是女生.
其实很简单的 只是读起来比较像罢了!
补充：你的第2个例子是错的,可能你是认为正确的!
What are these?那些是什么
回答They are apples.他们是苹果!
如果要回答There are apples!
那么提问要
What are there?那里有什么!

there are是有的意思，they are是他\她\它们.
There be+something+介词短语