二甲戊灵乳油一般检测哪几项指标?
参考答案:二甲戊灵乳油一般检测含量,PH值,乳化稳定性,水份。
如图为自来水厂净水过程的示意图,请判断净水过程中有化学变化发生的是( )
A.从水库取水
B.通过过滤池
C.通过活性炭吸附池
D.投药消毒
He _____ the bag, but saw nothing in it. [ ]
A. looked through
B. looked into
C. looked out of
D. looked up