二苯碳酰二肼分光光度法测定环境空气中六价铬时，吸光度测定时，用水作参比。
参考答案：对
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Which of the following statements is not tree()
A. To do yoga is to solder a union between mind and body
B. Yoga heals you by relaxing you.
C. Your deep breathing can release your muscle tension.
D. People in the US rush from their high-pressure jobs to yoga classes.
