Betty is _________careful as I, but I’m _________ than you.
When I walked past her room, I heard her _______ an English song.
Keep the machine _______, and you will know how it works.
—What was Tom doing _______ it was raining? —He was doing his homework in the bedroom.
Yesterday, a man said he saw _______ UFO in the park. The police are looking for _______ UFO now.
He _______ eight hundred thousand dollars for his Benz(奔驰) car.