直接配制法配制标准滴定溶液，其基准物应是（）。
参考答案：容量分析基准试剂
–I’m _____ to eat an elephant now! ---Oh, dear. But I don’t have ______ for you.
A hungry enough ; many food B hungry enough; enough food
C enough hungry; enough food D enough hungry; food enough
检查人体必需脂肪酸是否缺乏的灵敏指标是血中的（）。
A.十八碳三烯酸浓度
B.十六碳三烯酸浓度
C.二十碳三烯酸浓度
D.二十碳四烯酸浓度
E.二十碳三烯酸与二十碳四烯酸的比值
