题目

       In July 1994 ,Jupiter ,the largest planet in our solar system ,was struck by 21 pieces of a comet（彗星）. When the fragments（碎片）landed in the southern part of the giant planet ,the explosions were watched by scientists here on the earth .But what if our own planet was hit by a comet?        The year is 2094. It has been announced that a comet is heading towards the earth. Most of it will miss our planet, but two fragments will probably hit the southern part of the earth. The news has caused panic.        On 17 July, a fragment four kilometers wide enters t2010年，云南省遭遇了百年一遇的旱情，给工农业生产和生活用水带来了严重困难．为缓解旱情，有关部门实施了人工降雨．李斌同学利用所学知识将浑浊的水用右图所示的简易净水器进行净化，请根据你掌握的知识回答：（1）净水器中用来作吸附剂的物质是    ；（2）将浑浊的水变清的简单方法是    ；（3）澄清后的水加肥皂水后，若水中出现较多浮渣，该水为：    （选填“硬水”或“软水”）．（4）天然水中病原微生物过多、硬度大，都可以采取    方法，来杀灭病原微生物和降低水的硬度．（5）抗击旱灾，从我做起，你对节约用水的建议是：    （写一条即可）．