Where's my pen? [ ]
A. It's in the desk.
B. It's under the desk.
C. It's on the desk.
答案:B
5-Br-PADAP分光光度法测定水中锑时,在锑化氢的发生吸收装置中,校准曲线与水样测定相丝,多加了一种()试剂。
A.酒石酸溶液
B.碘化钾溶液
C.硫脲溶液
D.(1+1)盐酸溶液
7LS采煤机的JNA控制系统由()、()、()三个单元组成。