题目

现将粗盐提纯，并用制得的精盐配制50 g质量分数为8%的氯化钠溶液。下列说法正确的是( ) A.蒸发滤液时，待蒸发皿中滤液蒸干后停止加热 B.配制该溶液需要氯化钠8 g，水42 g C.粗盐溶解和过滤操作时，都用到了玻璃棒，玻璃棒的作用相同 D.配制溶液需要经过计算、称量、量取、溶解、装瓶、贴标签等步骤I had not seen him for years,but I_________ his voice on the phone. A. realized                       B. heard C. discovered                     D. recognized