It's difficult for him to succeed, but I hope he can _ it. [ ]
A. do
B. get
C. make
答案:C
高效液相色谱法分析水中酚类化合物时,样品在富集之前,应选()试剂以控制PH为2.
A.盐酸
B.硝酸
C.硫酸
底边