世界最大的淡水湖是（　　）

已知：a+b=1，ab=﹣4，计算：（a﹣2）（b﹣2）的结果是（　　）

84消毒液是一种有刺激性气味的高效液体消毒剂．主要成分为次氯酸钠（NaClO），广泛用于宾馆、旅游、医院、食品加工、家庭等的卫生消毒．请阅读信息并回答：

（1）次氯酸钠的制取原理是氯气与氢氧化钠反应生成氯化钠，次氯酸钠和水，化学反应方程式为　____ ；

（2）消毒液中次氯酸钠自身没有消毒作用，有消毒作用的是次氯酸钠与空气中二氧化碳反应得到的次氯酸（HClO），化学方程式为　____　；

（3）84消毒液是含氯消毒剂，氯气是一种挥发性的有毒气体，因此，84消毒液必须____保存．

张老汉有一个不争气的儿子，整天好吃懒做，参与赌博，还经常对不能满足其经济要求的父母非打即骂。有一天，儿子又去抢张老汉仅有的一点粮食，张老汉实在忍无可忍，抄起铁锨打向儿子，结果导致其儿子当场死亡。张老汉的行为属于(      )

    I remember believing in Santa when I was a very young girl. However, as I grew older, I learned many 1 that “proved” his nonexistence. Always2by nature, I was determined to use 3to decide whether Santa Claus was 4.

    The first test5when I was 5, I decided that if I6all night on Christmas Eve, I could see if Santa really came down the chimney7 that was a useless8 I fell asleep that year, and when I woke up, I saw a 9 wrapped present under the10

    At the age of 7, I came up with another test to see if Santa was real. That year, I didn't send out my Christmas letter to Santa because I wanted 11for Christmas. But this turned into a plot. By then, I 12knew Santa wasn't real, but I wanted enough13to support this. That year was 14. Because on Christmas Eve, my mother dragged me to our local Wal-Mart led me around the toy section. I 15 to say a word, but did let my eyes16on a ballet set. I17that “Santa” wouldn't know what I wanted because he shouldn't be able to read my 18However, my mother would know everything that caught my eyes in the store. If I got the ballet set the next morning, I would have my evidence. On Christmas morning, there was the ballet set, sitting under the tree again.19I didn't use it much, my mother ended up returning it a few days later. She20 Santa was generous enough to leave a receipt. That was the end to my task to discover the existence of Santa.