活性炭吸附-铬天菁S分光光度法测定水中铍时,六次甲基四胺缓冲溶液的最佳PH值为6.5.
参考答案:错
解析:六次甲基四胺缓冲溶液的最佳PH值为5.0.
In the world of sport, the four-minute mile—the "dream mile"—until recently was the most intriguing goal remaining to the individual athlete.
A.dating
B.demanding
C.thought-provoking
D.fascinating
American Indians________about five percent of the US population.[ ]
A.fill up
B.bring up
C.make up
D.set up