is this your case,is this case yous这两种语法有没有错误

Is this your pencil case中文 is this your case,is this case yous这两种语法有没有错误 Exuse me!Is this your pencil case?改为复数形式 is this a pen ___ your pencil case This is a new pen.( ) it in your pencil case Is this your watch in the lost and found case?怎么翻译?特别是case Ok,and this is my book and this is your pencil case ,Jane. This is his pencil case. what ( )is your pencil case? OK.and this is my book.And thr is your pencil case Jane 连词成句 notebook your this is in lost found ang case theoh，no。搞错了应该是notebook your this is in lost found and case the is this your case 语法错误吗?为什么我学新概念一的时候 有一句话 这是你的箱子吗？文章中的翻译is this case yours?我不解这种用法？用Is this your case This is your case.变复数……This is your case.It is a green dress.My blouse is new.I'm a teacher.This is a black and grey shirt.变复数要正确的急+++分 将下列句子变成复数形式My blouse is newMy blouse is newI'm a teacher This is your case this is my book.写出下列句子的复数形式 还有Is that his uncle Is she your friend?yes,it is.this is my pencil case. 变复数形式.1、This is his case.2.this is her hat.3.this isn,t my passport.4.is this your coat ? notebook your this is in lost found and case the 连词成句 is this your pencil case?___a 、yes,it's b 、no,it isn't