将下列句子改成否定句,一般疑问句,并作肯定句回答

1.Is this a bag?
Yes,it is.
This isn't a bag.
2.Is that my bike?
Yes,it is.
That isn't my bike.
3.Are you a bus driver?
Yes,I am.
You are not a bus driver.
4.Is Mary Green in office?
Yes,she is.
Mary Green isn't in office.
5.Are you English teachers?
Yes,I am.
You are not English teachers.
6.Are Peter's shoes black?
Yes,they are.
Peter's shoes are not black.
7.Are we in the classroom?
Yes,we are.
We are not in the classroom.
8.Are their knives new?
Yes,they are.
Their knives are not new.
By the way.我个人觉得第五句应该有些错误吧,原句应该是You are a English teacher.这样吧