题目

最美乡村教师刘月升 When we talk about village teachers, we often think of difficult conditions, heavy teaching tasks and little income. But there is a village teacher who makes his teaching job so interesting. His name is Liu Yuesheng who is now called “the most beautiful teacher”, Liu comes from Liugang Village Middle School in Dagang, Tianjin. The school is a rural area middle school. It has only about more than 300 students and teachers. Though the school is small, it is only a village school that takes the municipal (市级的) scientific research projects in Tianjin. S根据题意回答问题（在下列（1）、（2）两小题中任选一题回答，若两小题都回答，则以第（1）小题的答案来评定分数）（1）两个集气瓶中分别装着空气和氧气，如何区分？（2）如何区分过氧化氢溶液和水？