下列代号表示燃气类别的是()
A、JF
B、2L
C、6R
D、A
参考答案:C
The _____ in temperature is broadcast twice a day in the channel.
A.diversion
B.variety
C.variation
D.diversity
以C18柱为固定相、乙腈-水为流动相()
A.反相离子对色谱
B.反相色谱
C.正相色谱
D.离子交换色谱
E.离子抑制色谱