题目

Your schooldays should be some of the best and happiest days of your life. You shouldn’t waste this wonderful opportunity to learn. Here is our advice for you to have a happy school life.Advice 1  Be active in school! Don’t say things are difficult or boring. Be interested in school life and your school subjects. Join lots of activities. Be quick to put your hand up. Go around the school with a big smile.Advice 2  Expect to work. School is not a holiday camp. If you are not working，you are not learning，and you are wasting your time at school. Teachers cannot make everything enjoyable下列关于钠及其化合物的说法正确的是A．金属钠可以与金属钾形成一种合金B．金属钠在空气中久置最终转化为NaHCO3C．氧化钠在某些呼吸面具中用于制备氧气D．Na2CO3溶液能跟酸溶液反应，但不能跟碱溶液反应