1.He is a doctor.
(-)He isn't a doctor.
(?)Is he a doctor?
2.That is a book.
(-)That isn't a book.
(?)Is that a book?
3.She lives on Pham Hung street.
(-)She doesn't lives on Pham Hung street.
(?)Where she lives ?
4.They are students.
(-)They aren't students
(?)Are they students?
5.These are my classmates.
(-)These aren't my classmates
(?)Are these my classmates ?