测定硬度之前，应该先用（）清洗滴定管3次。
A.EDTA
B.盐酸
C.硝酸银
D.氨-氯化铵溶液
参考答案：A
贷款行的申请书上应加盖存款人在存款行的（）
A、预留印鉴
B、存款人公章
C、存款人财务专用章
Carbon dioxide as a fire fighting agent has which advantage over other agents?（）.
A.It causes minimal damage
B.It is safe for personnel
C.It is cheaper
D.It is most effective on a per unit basis
