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【单选题】第二篇 Sleep We all know that the normal human daily cycle of activity is of some 7 - 8 hours’ sleep alternating with some 16 - 17 hours’ wakefulness and that, broadly speaking, the sleep n...
A.
people hate the inconvenience of working on night shifts.
B.
your life is disturbed by changing from day to night routines and back.
C.
not all industries work at the same hours.
D.
it is difficult to find a corps of good night workers.
【单选题】绿色环保是化学实验的追求，下列操作不会引起空气污染的是
A.
用浓盐酸洗涤加热KMnO4制氧气的试管
B.
用稀硝酸洗涤做过银镜实验的试管
C.
硝酸亚铁和硫酸废液一同倒入废液缸
D.
将打破的水银温度计插入硫粉中
【多选题】有关铂皿使用操作正确的是（）
A.
铂皿必须保持清洁光亮，以免有害物质继续与铂作用；
B.
灼烧时，铂皿不能与其他金属接触；
C.
铂皿可以直接放置于马弗炉中灼烧；
D.
灼热的铂皿不能用不锈钢坩锅钳夹取。