正相色谱的固定相为非(弱)极性固定相，反相色谱的固定相为极性固定相。 ( )
查看答案
由于化合物的结构改变,可使吸收峰向长波方向移动称为______ ;当化合物由于结构改变或受溶剂影响而是吸收峰向短波方向移动称为______ 。
已知盐酸溶液浓度为0.1200mol/L,MCa______ 2=74.10,则THCl/Ca______ 2= ______ g/ml。非水滴定中,除去冰醋酸中的水用______
中国人过去习惯早婚。The best translation is "______".
A. It was the custom with the Chinese to marry early
B. Getting married early is the custom of the Chinese
C. For the Chinese, to get married early was their habit
D. It was the practice of the Chinese to marry early
在短短几个小时内就下了70毫米雨。The best translation is ______.
A. 70 millimetres of rain came down in just a few hours
B. 70 millimetres of rain fell in just a few hours
C. It rained 70 millimetres of rain in just a few hours
D. It poured down 70 millimetres of rain in just a few hours
微信支付 
支付宝支付