A centrifugal pump may fail to deliver water when first started if the （）. ["water seal pipe is plugged","pump is not primed","seal ring is improperly located","impeller is flooded"]
企业战略是指企业为了实现其战略目标而进行的全局性谋划与整体性决策。
No jettison of cargo shall be made fair as（）unless such cargo is carried in accordance withthe recognized custom of the trade. ["General average","Charter Party","Bill of Lading","Policy of Cargo Insurance"]
利用压力推算法可推算出注水井的（）。 ["油压、套压、启动压力","油压、静压、启动压力","套压、流压、启动压力","静压、流压、启动压力"]
以下概念中和ATM的流量控制、拥塞控制有直接关系的是（）。
热水采暖管道系统中，“上供”、“下回”各是什么含义？
