题目

--- Lucy, how old is your grandmother this year?. --- ______. And we are planning to have a birthday party for his ______ birthday this Saturday. A. Ninety; ninetieth                 B. Ninety ; the ninetieth    C. Ninty , the ninetieth               D.Ninety ; nintieth 答案：A（2013?高淳县一模）梅雨季节，固城湖水会浑浊．为了弄清梅雨季节湖水的水质状况，某化学兴趣小组对固城湖水质进行了相关调查．（1）取回水样，向浑浊的水中加明矾明矾，静置后过滤，得到澄清的水．（2）若要测定固城湖水的酸碱度，最适宜的试剂或用品是BB（填序号）．A．紫色石蕊试液     B．pH试纸      C．石灰石      D．无色酚酞试液（3）同学们通过对比实验，用肥皂水肥皂水可判断固城湖水是硬水还是软水．（4）生活中常用煮沸煮沸的方法，降低水的硬度，并且还能消毒杀菌．