帮我把英语改成否定句和一般疑问句

否定句
1this is not an eraser.
2this is not your pen.
3this is not your pencil.
4that is not your ruler.
5that is not my ruler.
6it's not a pencil case .
一般疑问句
1 Is this an eraser?
2 Is this your pen?
3 Is this your pencil？
4 Is this your ruler？
5 Is this my ruler？
6 Is it a pencil case ？

在所有is后加上not，就是否定句；把所有的is提前，其它的不变，如：Is this an eraser?就是一般移问句

1this is an eraser
否this isn't an eraser
疑is this an eraser?

2this is your pen
否this isn't your pen
疑is this my pen?

3this is your pencil.
否this isn't your pencil.
疑is this my pencil?

4that is your ruler
否that isn't your ruler.
疑is that my ruler?

5that is my ruler
否that isn't my ruler.
疑is that your ruler?

6it's a pencil case.
否it isn't a pencil case.
疑is it a pencil case?