用人单位与劳动者约定合同终止时间的劳动合同是（） ["固定期限劳动合同","无固定期限劳动合同","短期劳动合同","长期劳动合同"]
The amount of fluid delivered by a centrifugal pump can be regulated by （）. ["throttling the pressure line","changing the speed of the rotor","either A or B","None of the above is tree"]
政策性激励是指什么？
While flowing through the volute in a centrifugal pump, part of the （） energy of the liquid is converted to （） energy. ["kinetic；pressure","kinetic；essential","pressure；kinetic","pressure；height"]
PowerPoint 2003中，关于幻灯片放映的说法中正确的是（）。 ["使用键盘上的PageUp、PageDown键或上下箭头键，可以切换到上一张或下一张幻灯片演示","在最后一张幻灯片放映完后，单击鼠标，返回原视图","除非全部幻灯片播放完毕否则不能回到原视图","单击鼠标按钮，则可切换到下一张幻灯片演示","按ESC键可以返回原视图"]
集气管发生煤气放散后如何进行处理？
