配位滴定中,用于配制溶液的去离子水应不含三价铁离子、铝离子、铜离子、镁离子、钙离子等杂质离子。
A. 对
B. 错
以碳酸钙为基准物标定EDTA时,为使终点变色明显,必须加入镁溶液。
A. 对
B. 错
Under her leadership, the group’s ______ grew from less than one million dollars to more than ten million.
A. data
B. budget
C. item
D. piece
Her friend knows where he can ______ a good used car for her at a reasonable price.
A. choose
B. pick out
C. pick up
D. reach