题目内容：

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

优质解答

（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!...

追问：

不好意思 我打错了几个 （2）This is a pen and that's a ruler.没有问号,但是有错的 （3）Is this his pencil？————Yes,it's

追答：

（2）This is a pen and that's a ruler.没有问号,但是有错的 修改为：This is a pen and that is a ruler. 此为并列结构，is 最好缩写，或者都缩写 （3）Is this his pencil？————Yes,it's 应该为：Yes，it is. is不应缩写。