一个流程的生产能力取决于流程的（）。
The valve that prevents water from backing out of the boiler into the feed line is the（）. ["bottom-blow valve","skin valve","feed-check valve","feed-stop valve"]
对330～500kV线路，应按什么原则实现主保护的双重化？
A wave entering（）is likely to produce bores． ["shallow water","deep water","river","tide"]
画出WK-2型光控器外部接线图。
空闲时间是指工作时间没有执行（）的那段时间。
