Your shoes are too dirty. You’d better________.
Tom used to ______ short and fat, didn’t he ? —Yes, he did. Now he’s tall and thin.
— Where’s Lucy ? — She ________ in the office. I saw her there just now.
— How do you study English so well? — I study ________ reading English magazines.
—Look at the sky! What is it? —Oh! _______UFO is landing on the ground.
——Could you tell me ____?——It’s twenty minutes by underground.