题目

 I think itthat she should be knowledgeable about computers for her present job.  A. urgent           B. normal     C. essential         D. temporary 答案：C6．要配制500g溶质的质量分数为40%的硫酸铜溶液，计算：①需要溶质的质量分数为60%的硫酸铜溶液多少克？②加水多少克？