a table
It isn't a table.
pencils
They are pencils.
teachers
They aren't teachers.
a giraffe
It is a giraffe.
students
They are students.
happy
He isn't happy.
a policeman
He isn't a policeman.
one year old
It is one year old.
a lion
It isn't a lion.
yellow
They are yellow.
a dancer
She is a dancer.
a doctor
She isn't a doctor.
a chair
It is a chair.
rulers
They aren't rulers.
sad
He is sad.
three years old
It isn't three years old.
a teacher
He is a teacher.
a dog
It is a dog.
pink
They aren't pink.
a cat
It isn't a cat.