-- Look at the boy running on the ground. Is it David?-- It _______ be him. I saw him go to the teacher’s office just now.
Lucy is ill.She has a bad cold for several days.
Yougo and ask Tom.Heknow the answer.
—I put the bike here? —No,you can’t.
—Who is knocking at the door? —It be Miss Zhang.Because she has just gone to Japan.
—Must I finish my homework now? —No,you .