题目内容：

Exuse me!Is this your pencil case?改为复数形式

优质解答

Excuse me!Are these your pencil cases?

追问：

Yes, it is.It's my pencil case. Here you are. Thank you. Where is my dictionary? Sorry,I don't know改为复数形式

追答：

Yes, they are. they are my pencil cases? Here you are. Thank you. where are my dictionaries? Sorry, i don't know!