饮用水适宜的氟浓度一般为()。 A.0.5ppm B.0.7~1ppm C.1.0~ 发布时间:2017-08-15 06:51 │ 来源:www.tikuol.com 题型:单项选择题 问题: 饮用水适宜的氟浓度一般为()。A.0.5ppmB.0.7~1ppmC.1.0~1.5ppmD.2.0ppmE.以上均不是
题型:单项选择题 The doctor advised Versa strongly that she should take a holiday,but ______ didn’t help.A.itB.sheC.whichD.he 查看答案