吸烟之危害，可谓大矣，其严重性是不能低估的。吸烟污染空气，损害健康，使肺癌发病率大大增加。为了使各国人民关注烟草的盛行及预防吸烟导致的疾病和死亡，世界卫生组织已将每年的5月31日定为"世界无烟日"。瘾君子们说，一天饭不吃可以，一个时辰不抽烟就难捱了，不能戒。只要真正意识到吸烟有百害而无一利，于人于己都是一种祸害，就有可能下决心摆脱烟草的诱惑。戒烟贵在坚持，坚持下去就是收获。

　　参考译文：

　　Smoking does great harm to human and its gravity should not be underestimated.Smoking pollutes air,damages health,and increases the incidence of lung cancer.To arouse the awareness about the prevalence of tobacco in all the countries and to prevent smoking-induced diseases and deaths,the WHO (World Health Organization) has defined May 31stin every year as World No-Tobacco Day.The tobacco addicts say that smoking is impossible to quit because they could do without meals in a day but would feel tortured without tobacco in two hours.However,when one realizes that smoking is harmful in many ways but beneficial in no way and that it is a curse to others as well as to he himself,he will be determined to resist the temptation of tobacco.To quit smoking requires persistence and so long as one persists,he'll be rewarded.