is that your a book?哪里错了

题目

is that your a book?哪里错了
This is a pen and that's a ruler?
Is this his pencil?哪里错了!求

答案

（1)Is that your a book? 哪里错了your 和 a 不能同时使用改为：Is that your book?或：Is that a book?（2）This is a pen and that's a ruler? 应为肯定句,因此去掉问号.（3）Is this his pencil?此题正确!...