Tom and Mike are good friends. They are kind to children. They want to find summer jobs. One day Tom tells Mike that Beidaihe Kids Summer Camp needs help with sports, music and computers. They are both very glad to hear(说) this. Tom can play basketball and volleyball, and he can swim, too. Mike can play the violin, the trumpet, the drums and the guitar. Tom and Mike like computers very much. Can they join the Summer Camp?

阅读下列材料及茶卡盐湖位置图，回答问题。

    地处柴达木盆地的茶卡盐湖是有名的天然结晶盐湖，湖面海拔3100米，与其它盐湖不同的是，茶卡盐湖是固液并存的卤水湖，镶嵌在白雪皑皑的雪山和品种繁多的草地间，湖面似镜子一样反射天空景色，被旅行者们称为中国的“天空之镜”。湖畔生长的茶卡羊，羊肉富含矿物质和维生素，自古冠以“贡羊”之誉。但由于基础设施薄弱、流通体系不健全等原因，像茶卡羊这样的绿色食品未得到充分开发。2016年10月31日“中粮茶卡羊生态养殖基地”挂牌，以利用“互联网+”快车，加快绿色产品市场化、网络化步伐，尽快走出青海。

单糖是（）