If not attached to the nozzle,each low-velocity spray applicator on a vessel must be stowed（）. ["in a protected area on the main deck","inside a machinery space near the entrance","next to the fire hydrant to which the fire hose is attached","on a rack inside the quarters near the entrance"]
不同商品之间存在着差异，同一商品之间不存在差异，劳务也是一种商品，因而同一种劳务之间也应没有差异。
影响企业营销的宏观环境有哪些？微观环境有哪些？
（）数据库由国际农业和生物科学中心（CABI）提供。 ["PQDD","CAB","AGRICOLA","IEL"]
什么是市场营销环境？它具有哪些特征？
孕前保健的概念是什么？
