题目

Dear editor, Several days ago, I heard that a dear friend of mine had killed herself. I was deep in sorrow by the sudden news. I can't keep calm any longer. 16_____.  Life is so precious. If we can slip into death in an impulsive (冲动的) moment, what use in all our efforts and hopes? Our families, our ambitions, everything is flung into total darkness. 17_____.  Nevertheless, the suicide rate increases year by year, particularly of young people. Reasons may vary from person to person, 18_____.   First, today's young people are morally weak. They hunger for success but can not fa把0.5：化成最简整数比是________：________，比值是________．