His books are in the backpack 对这个句子做肯定回答以及否定回答

问题描述:

His books are in the backpack 对这个句子做肯定回答以及否定回答
急啊,马上就要,明天教啊,帮帮忙

Are his books in the backpack
Yes ,they are .
No ,they aren't .