色谱柱长2米, * * 论塔板数为1600,若将色谱柱增加到4m,理论塔板数(/米)应当为()。
A、3200
B、1600
C、800
D、800
参考答案:A
甲数是7,乙数是42,乙数是甲数的几倍?
The picture shows us _______ in Nanjing in the past.
A.what everyday life was like
B.what was everyday life like
C.how everyday life was like
D.how was everyday life like