The dumping of refuse in a lock is permitted（）. ["when approved by the lockmaster","when locking downbound","at no time","during high water only"]
街面治安巡察时在礼仪上应注意哪些？
“易燃液体”和“氧化剂”分别属于（）类危险化学品。 ["4；3","3；5","5；3","2；7"]
The control rod of a steering gear pump is attached at its outer end to （）. ["the hunting gear","the rudder stock","the rudder controller","the feedback unit"]
以下现金成本与现金持有量成正比例关系的是（） ["现金置存成本","现金交易成本","现金管理成本","现金短缺成本"]
规模经济是指生产单位产品的成本随生产规模的增加而（）。
