-- 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.
-- What do you think of her acting skills? ---Oh, no one does_______.
She told us that her brother ______ the Army for 3 years.
---Are the new rules working? ---Yes. _______ books are stolen.
--- Look! What's in_______ sky? --- Oh, it's _______ UFO. I wish I could fly in_______ space some day.
–– Would you like to play table tennis with us after school? –– _________.