下列应用及相应的原理（用化学方程式表示）的是（　　）

材料一：2016年2月29日，人力资@源社会保障部部长尹蔚民在国务院新闻办举行发布会，介绍就业和社会保障有关情况。据人社部统计，我国2015年城镇新增就业1312万人，同比下降了0．8%。在关于2016年我国就业形势问题上，尹蔚民表示，16年，我国就业形势依然复杂。

材料二：2010年，国家财政加强惠民支出，教育投入、农民和城镇居民基本医保、社保投入、保障性住房建设和水利建设五大类支出大幅增加，从而增加人民收入，改善民生。这表明，我国在社会财富“蛋糕”显然做大的同时，更加注重如何“切蛋糕”，实现“国强”到“民富”的转变。

    You want to know about my staying in America, right? Well, to tell you the truth, it is really an eye-opening experience to study here.
In China, I had English classes five times a week since fifth grade. However, I didn't know how different textbook English could be from everyday English until I came to Hotchkiss School, Connecticut.
When I first studied English, I was told to say,” I am fine” when people say “How are you?” But in the US, I found that people say, “I am good” or “I'm tired”.
    One day, someone greeted me with “What’s up?” It made me confused . I thought for a moment and then smiled because I didn't know what to say.
    Since then, I have discovered more and more differences between Chinese and US cultures.
    To my surprise, US girls spend a lot of time in the burning sun to get a tan(晒黑). However, in China, girls try every possible way to get their skin paler, or “whiter”.
    I was also surprised by how hardworking US students are.  In China, schoolwork is almost everything, so we study hard and that's it. But here, a “good” student gets good grades, does a lot for the public and plays sports or music.
    The kids here are so talented, I am starting to be sorry that I gave up playing the piano at an early age and that I have never thought about sports.