有人工作或可能到达的井巷，二氧化碳的浓度不得大于（），总回风流巷中，二氧化碳的浓度不超过0.5%。
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J2-7型空气制动机中均管泄漏时.白阀手柄前五位与均衡风缸泄漏现象相同，取柄位时，均衡风缸排气速度正常，制动管压力逐渐下降。
A. 正确
B. 错误
A vessel is heading magnetic northwest and its magnetic compass indicates a heading of 312°. What action should be taken to remove this error during compass adjustment? （）
A. If the quadrantal spheres are all the way out，replace them with smaller spheres
B. If the quadrantal spheres are all the way in，replace them with larger spheres
C. If the quadrantal spheres are all of the way out，move the spheres in
D. If the quadrantal spheres are all the way out，replace them with larger spheres.
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