完形填空。

   1! My name  2Alice. I'm fourteen  3  . I like playing Volleyball  4 going to the cinema. My favourite5  is Christmas.

    This is my friend Joe. He's fifteen. He   6  like playing sport. He can7  English and he likes Maths. He wants8   everything about it.

    This is my cousin. She is thirteen.   9 favourite sport is skating and she can skate very   10   . She likes music. She says it's exciting.

三江源地区是长江、黄河和澜沧江的源头汇水区。三江源地区曾是河湖密布、水草丰美的高原草甸区。目前，三江源地区众多江河、湖泊和湿地缩小、干涸；水土流失的面积不断扩大；荒漠化和草地退化问题日益突出。为改善三江源地区生态环境，必须采取的有效措施是（　　）