题目

NaCl溶液中含有Ca(HCO3)2、MgSO4、CaSO4等杂质，其除去方法正确的是 A．Ba(OH)2溶液→Na2CO3溶液→盐酸  B．Ba(OH)2溶液→盐酸→Na2CO3溶液C．Na2CO3溶液→Ba(OH)2溶液→盐酸      D．盐酸→Na2CO3溶液→Ba(OH)2溶液 答案：AWe can get some ________ about how to use the Learning APP through the official account.A.information B.idea C.tip D.suggestion