12，20，16，18，20，28，23，16，15，18，20，24，18，21，18，19，18，31，18，13，

求这组数据的平均数，中位数，众数．

完形填空题

     My family members like to use computers. We live in China. My aunt1in Australia. My mother and my aunt often2e-mails to each other. Sometimes3chat(聊天) online.

     My father is a4in a middle school. He often searches for5for his lessons6the Internet.

     My brother and I like to7computer games. I like to play Counter Strike, but he likes to play Seer(赛尔号). My8don't like us to play them too long. They say that playing computer games too long is bad for our9and study. We both like music, too. So sometimes we10music on the computer.