Выберите правильную форму глагола BE.

My friend (am, is, are) playing in the yard now.
I (am, is, are) writing an exercise at the moment.
They (am, is, are) doing homework at present.
Look!He (am, is, are) smiling at us.
Listen! The birds (am, is, are) singing in the garden.
We (am, is, are) going for a walk.
She (am, is, are) making a pie.
Listen! The dog (am, is, are) barking at the door.