英语高手进来啊~~~

That is not your ring.

Are these her books?

Whose oranges are those?

Those are not my backpack.

These are my watches.

These are his dictionaries.

These are some pencil cases.

Those are their friends.

These are English books.

最后2题本身不就是复数吗

That is your ring(改成否定句)
That isn't your ring

These are her books（改成一般疑问句，并做否定回答）
Are these her books,no,they aren't

Those are his oranges(划线部分提问)
___________
Whose oranges are those?

Those are my backpack(改成否定句)
Those aren't my backpack

This is my watch(改成复数形式)
These are my watches

This is his dictionary(改成复数形式)
These are his dictionaries

This is a pencil case（改成复数形式）
These are the pencil cases

Those are his friends(改成复数形式)
这句已经是复数形式了（单数形式是This is his friend）

These are English books(改成复