把下列英语句子改为否定句,一般疑问句,肯定回答句,否定回答句

1.This is not my ruler,Is this your ruler?--Yes,it is /No,it isn't
2.My brother is not a student,Is your brother a student?--Yes,he is /No,he isn't
3.Mike and Amma are not students.Are Mike and Amma students?--Yes,they are/No,they aren't.
4.I am not a doctor.Are you a doctor?--Yes,I am/No,I am not.
5.He is not my brother.Is he your brother?--Yes,he is /No ,he isn't.