A.<0.3ppmB、0.4~0.6ppmC、0.7~1.0ppmD、1.5ppmE、2~4ppm
[单选题]能引起慢性氟中毒的氟浓度是A.<0.3ppmB、0.4~0.6ppmC、0.7~1.0ppmD、1.5ppmE、2~4ppm
[单选题]我国现行水质标准氟浓度为A.0.1~0.4ppmB.0.01~0.05ppmC.0.5~1.0ppmD.1.1~2.0ppmE.>2ppm
[单选题]既能有效地防龋又不至于发生氟牙症的水氟浓度是A.0.5ppmB.0.7ppmC.1.0ppmD.1.2ppmE.1.5ppm
[单选题]适宜的饮水氟浓度为A.低于0.4mg/LB.0.4~0.7mg/LC.0.7~1.0mg/LD.1.2~1.5mg/LE.1.5~2.0mg/L
[单选题]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
[单选题]氟化水源防龋的标准浓度是A.0.05~0.1ppmB.0.1~0.5ppmC.0.5~1ppmD.1~5ppmE.5~10ppm
[单选题]马钱子内服量应控制在A.0.2~0.4gB.0.3~0.6gC.0.5~0.7gD.0.6~0.8gE.0.8~lg
[单选题]十一点法相对水深0.0、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、1.0的测点流速分别为1.20m/s、1.40m/s、1.50m/s、1.50m/s、1.40m/s、1.30m/s、1.20m/s、1.00m/s、0.80m/s、0.60m/s、0.20m/s,则该垂线平均流速为()m/s。A .1.21B .1.12C .1.10D .1.14
[试题]十一点法相对水深0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0的测点流速分别为1.20m/s,1.40m/s,1.50m/s,1.50m/s,1.40m/s,1.30m/s,1.20m/s,1.00m/s,0.80m/s,0.60m/s,0.20m/s,则该垂线平均流速为()m/s。A.1.21B.1.12C.1.10D.1.14
[单选题]我国饮用水标准含氟量是A.0.1ppmB.0.5ppmC.0.5~1.0ppmD.1.5ppmE.2.0ppm