1. Those men aren't doctors. Are these men doctors? Yes, they are.
2. Kate isn't a teacher. Is Kate a teacher? Yes, she is.
3. The students aren't in that classroom. Are students in that classroom? Yes, they are.
4. My friend isn't a student. Is my friend a student? Yes, he is.
5. These books aren't good. Are these books good? Yes, they are.