I often watch TV ___seven ___ Sunday eve 发布时间:2017-06-09 13:24 │ 来源:www.tikuol.com 题型:选择题 问题: I often watch TV ___seven ___ Sunday evenings .A. in ;on B. at; on C. at ; in D in ; at
题型:选择题 粗盐中般含有Mg2+, Ca2+, SO42-,等离子,现进行粗盐的提纯,需将这些离子都除去,需要用到的试剂有如下几种: ①BaCl2溶液②Na2CO3溶液③NaOH溶液4稀盐酸,则添加的正确顺序是A.①②③④B.④①③②C.②③④①D.①④②③ 查看答案