怎样对一般疑问句做否定回答

1.改为一般疑问句
Is this my pen?
2.对一般疑问句做肯定回答
Yes, it's mine.
3.对一般疑问句做否定回答
No, it isn't (mine).
4.改为否定句
This is not my pen.
5.对划线部分提问
(实在是看不清你画的什么地方）
如果是划my或者是my pen
Whose pen is this ？
如果是划pen
What's this？

Is this your pen?
Yes, it is.
No, it isn't.
This is not my pen.
Whose pen is this?

1.Is this your pen?
2.Yes ,it is
3.NO,it isn't
4.This isn't my pen
5.Who is a pen?