判断题 毛细管电泳的进样量为微升级 A、正确 B、错误

单项选择题 When the guest asks about the charge standard of baby-sitting service, we can say:_____. A. Maybe it's very expensive. B. I don't know. C. You can have a try. D.  It is 10 yuan an hour, for a minimum of 4 hours.

单项选择题 某物质在某波长处的摩尔吸光系数很大，则表明 A、该物质对某波长的吸光能力很强。 B、该物质浓度很大。 C、光通过该物质的溶液的光程长。 D、测定该物质的精密度很高。

单项选择题 ​利用替换 ， 可把方程  化为新方程  （   ）‌

单项选择题 The following figure is the schematic of effectof heating temperature on microstructure and properties of cold-deformedmetals, which curve shows the change of grain size? A. A曲线 B. B曲线 C. C曲线 D. D曲线