Other configurations include an in- line flow indicator which changes color to green in the presence of oxygen
其他配置包括一个在线流量指示器，它在氧气存在时颜色变为绿色。
A.An in-line flow indicator is embodied in other configurations. If there is oxygen, the color of the indicator becomes green. B.The oxygen is dyed green in other configurations that include an in-line flow indicator. C.The present oxygen indicator comes on green due to an in-line flow in the other configurations.正确答案A
