Mice (not to be) big animals.
are not/aren't
She (to be) very tired.
is
This exercise (not to be) difficult.
is not/isn't
Lemons (to be) sweet? short answer (no)
Are lemons sweet? No, they are not. / No, they aren't.
Your classmates (to be) friendly? Short answer (yes)
Are your classmates friendly? Yes, they are.
You (to be) interested in football? short answer (yes)
Are you interested in football? Yes, I am.
Washington (to be) in America.
is
He (to be) married? short answer (yes)
Is he married? Yes, he is.
Mr and Mrs Jones (to be) teachers.
are
Amy (to be) 5 years old?
Is Amy 5 years old?
They (not to be) thirsty, they (to be) hungry.
are not/aren't....are
Europe and Africa (to be) continents.
are
Hockey (not to be) a slow game. It (to be) fast.
is not/isn't....is
An elephant (to be) a big animal.
is
It (to be) cold today.
is
Dogs (to be) man's best friend.
are
I (not to be) a teacher. I (to be) a student.
am not/ 'm not....am