题目

In the book The Best Little Girl in the World, Kessa has a serious eating disorder (进食障碍) called anorexia nervosa. But she is not alone. Many people have this eating disorder. In the beginning of her story, Kessa is a normal 15-year-old. She is good at many things, especially dancing. She has danced for many years and loves it. One day her dance teacher tells her to continue eating right, but maybe lose a few pounds. Once Kessa hears this, she takes things too far. Instead of cutting down on snacks and junk food, she decides not to eat at all. She does not eat breakfast, lunch, 通过近一年的化学学习，同学们已能用所学的知识回答一些问题：〔1〕煤、________、________常称为化石燃料；〔2〕天然水中含有许多杂质，可利用吸附、沉淀、过滤和蒸馏等方法净化，其中净化程度最高的方法是________、硬水给生活和生产带来很多麻烦，生活中可用________来区分硬水和软水；（3）服用含小苏打的药物可治疗胃酸过多，其反应方程式为________．