第10题: [单项选择]饮水加氟的适宜浓度是 A. 0.3~0.5mg/L B. 0.5~0.7mg/l C. 0.7~1.0mg/L D. 1.0~1.2mg/L E. 1.2~1.5mg/L 参考答案:C 答案解析:[解析] 这是一道自来水氟化的原则方面的选题,刘大维等认为自来水加氟应在 Dean规定的三条原则基础上遵循6条补充原则。饮水氟含量的适宜浓度应保持在0.7~1.0mg/L之内。
第28题: [单项选择]Congressional leaders have to work out a compromise because_________. A. a similar bill has been passed. B. the President might oppose the plan. C. the Senate bill was passed by 57 to 42. D. the White House is facing opposition. 参考答案:B