It is pencil case.改为复数是什么?0.0

It is pencil case.改为复数是什么?0.0 It's my pencil case 改为否定句This is her ruler 改为一般疑问句 where it is your pencil-case? There is a pen in my pencil case改为I () a pen in my pencil case It's his pencil case.(改为复数） It`s his pencil case.(改为否定句) Exuse me!Is this your pencil case?改为复数形式 That is a pencil case.(改为否定句) This is my pencil case改为复数形式 This is a pencil case.(改为复数句子） That is my pencil case（改为一般疑问句） My pen is in the pencil case改为一般疑问句? that is her pencil case改为一般疑问句 His pen is in the pencil case 改为否定句 my eraser is in the pencil case改为疑问句 把this is her pencil case 改为一般疑问句 This is my new pencil case 改为一般疑问句 My pen is in my pencil case.(改为一般疑问句)