一般水平管道应有不小于（）的坡度。A、1/1000 B、1/100 C、2/10

    On a Friday night, a poor young violinist was playing his violin at the entrance of the subway station. The
music was so great that people slowed to listen and put some money into his hat.
    The next day, the violinist came the entrance again. He put down his hat as usual. Beside the hat was a piece
of paper with some words on it. It said, "A George Sang has put an important thing into may hat by mistake.
Welcome to claim (认领) it." Soon the people were all attracted by the words and wondered what it could be.
After a while a man rushed through the crowd, took the violinist's shoulders and said, "I knew you would
certainly come here." The vilinist asked, "Did you lose something?" "Lottery ( * * )". The violinist took out a
lottery ticket with Sang's name on it. Sang took it and danced happily.
     Sang was an office worker. He bought the lottery and won a prize of $500,000. But when he gave $50 to
the violinist for his wonderful music, the lottery ticket was thrown in, too. The violinist was a college student.
That morning, he was going to fly to Vienna for high education. However, when he found the ticket, he
cancelled the flight and returned to the entrance.
     Later someone asked the violinist why he didn't take the lottery ticket to pay the tuition fee (学费). He said,
"Although I didn't have much money, I live happily. If I lose honesty, I won't be happy forever."