-_____ does your mother do?

-She is a teacher in a middle school.[ ]

A.Who

B.What

C.Where

D.How

硅钼黄光度法测定水中可溶性二氧化硅时，二氧化硅贮备液应贮于玻璃瓶中，并标准分析法校核其准确度。