---Did they have a good time at the party?---Judging by their smiles, they _________ have enjoyed themselves.

【There’s a lot of water on the ground; the water pipe _____ be repaired. 

--Listen! Tom is singing in the next room.--It _______ be Tom. He has gone to Shanghai. 

—Can you tell me what to wear at the party?—If I            you, I            the blue jeans.

— Must we wear our school uniform this afternoon?— No, you. All of us will go on an outing.