Your classmates (to be) friendly.
Your classmates are friendly.
I (not to be) a teacher. I (to be) a student.
am not/ 'm not....am
She (to be) very tired.
is
Lemons (not to be) sweet.
Lemons aren't sweet.
You (to be) interested in football.
You are interested in football.
This exercise (not to be) difficult.
is not/isn't
An elephant (to be) a big animal.
is
Dogs (to be) man's best friend.
are
They (not to be) thirsty, they (to be) hungry.
are not/aren't....are
Washington (to be) in America.
is
He (not to be) married.
He isn't married.
Mice (not to be) big animals.
are not/aren't
Mr and Mrs Jones (to be) teachers.
are
Europe and Africa (to be) continents.
are
Amy (to be) 5 years old.
Amy is 5 years old.
It (to be) cold today.
is
Hockey (not to be) a slow game. It (to be) fast.
is not/isn't....is