为了预防氟牙症和龋齿,我国水中氟的适宜浓度是 A、0.2~0.7ppmB、0.5~1.0ppmC、0.7~1.2ppmD、1.0~1.5ppmE、1.5~2.0ppm 发布时间:2023-07-26 06:37:26