Domestic water pump is started automatically by （） which operates as the water level falls to a predetermined level. ["a level controller","a temperature switch","a pressure switch","a floating ball"]
废弃危险化学品处置办法有（）。 ["地质处置","海洋处置","焚烧处置"]
在每天进行工作前要进行哪些检查工作？
MPEG-4动态图像压缩标准在信息描述中首次采用了“对象”（Object）概念。
社区民警如何选择恰当的时间走访居民？
简述沙市刺棘头病的病原。
