One of my friends Fred did very 1ittle work when he was a student. He spent more time drinking in bars  than working in the library. Once, we had to take an important exam. The exam had a hundred questions. To each question, we had to write "Right" or "Wrong". The night before the exam, Fred was watching TV and drinking. He usua1ly worried a lot the night before the exam. But on that night he looked quite relaxed. He told me what he would do." It's very easy," he said to me, "There are a hundred questions and I have to get fifty right answers to pass the exam. I'll bring a coin  with me and throw it to decide answers. I' m sure I'll get half the questions right in this way. "During the exam, Fred sat down and really threw the coin for half an hour when he was writing down his answers. Then he 1eft half an hour before the others. The next day he saw the teacher on the playground. "Good morning, Mr. Wu," he said, "Have you checked the papers? Have I passed?" The teacher 1ooked at him and smiled, "Ah, it's you, Fred. One moment, please." Then he put his hand into his pocket and took out a coin. He threw it into the air, caught it in his hand and looked at it , "I'm very sorry, Fred. You _ ." _  , the night before the important exam.
Fred was busy working on his lessons Both Fred and the writer were preparing the lessons Fred worried about the exam Fred was watching TV and drinking