题目

当弱电解质在溶液中达到电离平衡时，溶液中已电离的电解质分子数占原来总分子数的百分数叫做该电解质的电离度。现欲粗略测定一定未知浓度的醋酸溶液中的醋酸的电离度，应做的实验和所需的试剂（或试纸）是( ) A、蒸发、NaOH溶液             B、蒸馏、Na2CO3溶液 C、中和反应、石蕊溶液         D、中和滴定、pH试纸The suggestion ________ they are considering is ________ we should learn some practical.A.which; thatB.that; thatC.that; whichD.which; how