An instructor in chemical warfare asked soldiers in his class: "Anyone knows the formula for water?""Sure. That's easy," said one man."What is it?""H, I, J, K, L, M, N, O.""What, what?" reasked the instructor."H to O," explained the chemistry expert. 生化战争课的老师在课堂上问士兵们：“谁知道水的分子式？”“当然，太简单了。”一个士兵回答道。“是什么？”“H, I, J, K, L, M, N, O.”“什么，什么？”老师又问道。“H to O，”化学专家解释道。