It is really crazy ________ Peter to let his ________ son swim alone in the river.
— 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.
——Oh, I had a terrible toothache. ——You’d better see a dentist and have your bad teeth out.