A.小于50000μg/gB.50000~80000μg/gC.80000~100000μg/gD.高于100000μg/g
A.酸性B.碱性C.中性D.高温
A.清水→盐酸→水玻璃→清水B.清水→水玻璃→清水→盐酸C.清水→水玻璃→盐酸→清水D.水玻璃→清水→盐酸→清水