题目

Machines or learningThe classic model of education—a burst at the start and top-ups through company training—is _________. One reason is the need for new, and constantly updated, skills. Manufacturing _________ calls for brain work rather than metal-bashing. The _________ of the American workforce employed in routine office jobs declined from 25.5% to 21% between 1996 and 2015. The single, stable career has gone the way of the Rolodex.Pushing people into ever-higher levels of _________ education at the start of their lives is not the way to cope. Just 16% of Americans think that a four-yea称取含有杂质的石灰石（主要成分为CaCO3）样品6g放入盛有46.2 g稀盐酸的烧杯中，两者恰好完全反应，称得反应后所得物质的总质量为50g，(已知杂质不与稀盐酸反应)计算：（1）反应后生成的二氧化碳气体的质量为_________g；（2）原样品中CaCO3质量是多少________？（3）原样品中CaCO3质量分数是多少________？