游离酸的测定中用氢氧化钠标准溶液滴至黄色变成蓝色,过了几分钟又变为黄色,这时你该不该再补滴定,使其变为蓝色?
参考答案:不需要补滴定。滴定至终点后30s不褪色即可。
______ good , the fish was eating up in no time.
A.Smelt
B.Smelling
C.Having smelling
D.Being smelt
简述曹丕诗歌的特点。