根据短文内容判断正误，正确写“T”，错误写“F”。 Mark Twain (马克·吐温) was an American writer (作家). One day he went to a city by train. He wanted to see one of his friends there. He was a very busy man. He usually forgot something. When he was in the train, the conductor asked him for his ticket. Mark Twain looked for the ticket here and there, but he couldn't find it. The conductor knew Mark Twain. She said, 'Show me your ticket on your way back. And if (如果) you can't find it, it doesn't matter.' 'Oh, but it does,' said Mark Twain, 'I must find the ticket. If I can't find it, how can I know where I'm going?' (     )1. Mark Twain usually forgot something because he was very busy. (     )2. Mark Twain didn't want to show his ticket to the conductor. (     )3. The conductor didn't know Mark Twain. (     )4. Mark Twain bought a ticket before he got on the train. (     )5. Mark Twain remembered where he was going.