His teacher told him that since his parents were working abroad , either his grandparents or one of his uncles ______ allowed to come to the parents’ meeting .
【简答题】(11分)某校研究性学习小组到实验室进行探究实验。他们准备用加热高锰酸钾的方法制取氧气并验证氧气的性质。 (1)写出用该方法制取氧气的化学反应文字表达式 ______ ______________ __ (2)请指出图中所用仪器的名称: a _______ b c ______ _ d ________ (3)他们所用的装置图中有一些错误,请你为他们指出来 ①. __...