【简答题】4 “ My son has a kid now, so I don’t have to worry about anything, ” he said with ________ . (academic average dessert exchange experience fond satisfaction sculpture Spanish surf )
【单选题】过氧化氢水溶液俗称双氧水,过氧化氢易分解为水和氧气,常作氧化剂、漂白剂和消毒剂,为贮存、运输、使用的方便,工业常将H 2 O 2 转化为过碳酸钠晶体(其化学式为2Na 2 CO 3 .3H 2 O 2 ),它具有Na 2 CO 3 和H 2 O 2 的双重性质。下列物质不会使过碳酸钠晶体失效的是