空气压缩机基本分为三种，即活塞式、螺杆式、隔膜式。
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The procedures recommended for auxiliary boilers having high salinity include （）.
A. treating with oxygen scavengers
B. securing the boiler and giving it a blowing down
C. increasing the pH
D. reducing the phosphate level
胃管鼻饲法最危险并发症（）
A. 胃出血
B. 腹泻
C. 便秘
D. 胃食管反流、误吸
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