《秦律》规定，有事必须以公文的形式书面请示，不得口头请示或托人代达。这一规定的根本目的是(  )

2007年5月份，某市市区一周空气质量报告中某项污染指数的数据是：31 35 31 34 30 32 31，这组数据的中位数、众数分别是（　　）

    There is a man and he calls the police when he loses a pet. He a lways asks the police to help him look for it.

    “I lost my pet bird，”he tell the police one day.“She can sing songs. Can you find her for me?”

    “I'm sorry，”the policeman says.“It isn't our job（工作）to look for birds. If you leave a window open in your house，the bird may come back.”

    Another time，the man calls the police and says，“I lost my cat. （A）你能帮我找到他吗？He can  talk. ”

    “I'm sorry，”the policeman says.“（B）It isn't our job to look for cats. You should put the telephone down quickly. Maybe（也许）he is calling you now and tells you where he is. ”