我国饮用水标准含氟量是() A.0.0ppm B.0.5ppm C.0.5~1.0p 发布时间:2017-08-23 12:56 │ 来源:www.tikuol.com 题型:单项选择题 问题: 我国饮用水标准含氟量是()A.0.0ppmB.0.5ppmC.0.5~1.0ppmD.1.0~1.5ppmE.1.0ppm
题型:单项选择题 —How about your negotiations?—Pretty successful. Full exchanges of opinions allowed both sides of us to better understand ______ each stood on many issues. A.whereB.thatC.whatD.which 查看答案
题型:单项选择题 在石灰窑中烧制生石灰,1mol CaCO3完全分解所需要的能量,可燃烧0.453 mol碳来提供。设空气中O2体积分数为0. 21,N2为0.79,则石灰窑产生的气体CO2的体积分数可能是 [ ]A. 0. 43 B. 0.46C. 0.49D. 0.52 查看答案