【简答题】盐酸普鲁卡因注射液中检查对氨基苯甲酸杂质:精密量取本品,加乙醇稀释成每毫升中含盐酸普鲁卡因2.5mg的溶液,作为供试液。取对氨基苯甲酸对照品,加乙醇制成每毫升中含30μg对氨基苯甲酸溶液,作为对照液。取上述两种溶液各10μL,分别点于硅胶H薄层板上,用苯-冰醋酸-丙酮-甲醇(14:1:1:4)为展开剂展开,晾干后用对二甲氨基苯甲醛溶液显色。供试液所显的与对照品液相应的杂质斑点,其颜色与对照品溶液主...
【简答题】When people become unemployed, it is _____ ?When people become unemployed, it is _____ which is often worse than lack of wages. A) laziness B) poverty C) idleness D) inabil...
【单选题】下列描述中正确的是
C.
计算机运行速度可用每秒钟执行指令的条数来表示
【单选题】When does he try to smile at people and thank them?
A.
when people behave politely
B.
when people behave friendly
C.
when people behave kindly
D.
when people behave nicely
【简答题】When a population is said to be aging,______. [A] more people are retiring than people entering the workforce [B] the birth rate is growing [C] there is an oversupply of workforce [D] young people out...
【简答题】According to the article, when people feel too worried or nervous or when they overwork,
【单选题】The author implies that many people attribute Emily Dickinson's seclusion to ______.