吡唑啉酮分光光度法测定水中三氯乙醛,具有显色稳定的特点,量的Mn2+、C.U2+和Hg2+对测定有干扰,甲醛和敌敌畏没有干扰。
参考答案:错
解析:甲醛和敌敌畏对测定有干扰
— Mum, I am sorry, but I failed in the English exam.
— So you ________ get the MP4 you want. I am sorry, too. [ ]
A. shall not
B. might not
C. needn't
D. shouldn't
常用的炼焦用煤中,()单独炼焦,炼出的焦炭强度高、裂纹少、耐磨性好、块度均匀。
A.气煤
B.焦煤
C.肥煤
D.瘦煤