【单选题】89旅行社应当与通过其取得导游证的导游订立不少于( )期限的劳动合同。
【单选题】The ratio of the height of a vessel’s rudder to its width is referred to as the().
【简答题】A.investors B.developers C.designers D.stakeholders
【单选题】The width to height ratio most monitors have is .
【简答题】根冠比(root top ratio,R/T)
【简答题】the ratio of channel width to channel length
【判断题】低压电器元件的电气寿命一般比机械寿命大。