氟化水源防龋的标准浓度是A.0.5~1ppm B.5~10ppm C.0.1~0.5ppm D.1~5ppm E.0.05~0.1ppm

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问题 氟化水源防龋的标准浓度是

选项 A.0.5~1ppm
B.5~10ppm
C.0.1~0.5ppm
D.1~5ppm
E.0.05~0.1ppm

答案A

解析
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