is that pencil case?这句话哪里错了

is that pencil case?这句话哪里错了 that is my a pencil case 哪里错了 My pen is in pencil case.哪里错了? my pen is in pencil case 哪里错了? Is that () pencil case That is a pencil box 这句话哪儿错了 is that pencil case 怎么改? there have a pencil and an eraser in the pencil-case.哪里错了? That is a pencil case对a pencil case画线提问 Is that your computer game is the lost and found case?哪里错了! the pencil case is( ). That is my pencil case（改为一般疑问句）