— Look at the boy playing basketball on the ground. Is it George?— It ________ be him. He told me he would play basketball after class, but he’s not sure.

—Susan’s parents have bought a large house with a swimming pool.—It               be very expensive.

This book _______ be Tom’s. Look! His name is on the cover.

You         get up so early this morning because it’s Sunday today .

--- How’s your new babysitter?  --- We ______ ask for a better one. All our kids love her so much.