Thanks ______ your letters.[ ]
A. for
B. in
C. at
D. with
答案:A
将铁粉分别加入硫酸锌、硫酸铜、硝酸钾、稀盐酸等四种溶液中,能置换出的物质有()
A.锌、铜
B.铜、氢气
C.锌、钾
D.钾、氢气
关元穴的主治作用?