A. among doctors. B. among managers. C. between doctors and managers. D. between doctors and patients. 参考答案:D 答案解析:在倒数第二段有Dr Bruce Charlton的观点,他在文章中论述了the excessive informality of relations between professionals suc
第28题: [单项选择]现有一种预防禽流感药物配置成的甲、乙两种不同浓度的消毒溶液。若从甲中取2100克、乙中取700克混合而成的消毒溶液的浓度为3%;若从甲中取900克、乙中取2700克,则混合而成的消毒溶液的浓度为5%。则甲、乙两种消毒溶液的浓度分别为( )。 A. 3% 6% B. 3% 4% C. 2% 6% D. 4% 6% 参考答案:C 答案解析:[解析] 设甲、乙两种消毒溶液的浓度分别为x、y,
从甲中取2100克、乙中取700克混合而成的消毒溶液的浓度为3%,即2100x+700y=(2100+700)×3%;