be动词改否定句.请给我找25句!

1.I'm a teacher
Iamn't a teacher
2.I'm a student
I'm not a student
3,I'm a dancer
I'm not a dancer
4.I'm a writer
I'm not a writer
5.I'm a librarian
I'm not a librarian
are
1.They are teachers
They aren't teachers
2.We are students
We arenot students
3.You are dancers
You aren't dancers
4.They are writers
They aren't writers
5.We are librarians
We are not librarians