community intervention trial
（）属于湿法除尘。 ["布袋除尘","电除尘","喷淋塔","重力除尘器"]
患儿，男，5岁，于夜间11点来院就诊。哭闹不休，不断摇头、搔耳。家长诉以前无类似症状，1周前曾患感冒，近2日来出现以上症状。牵拉耳廓时未见症状加重。耳镜所见：整个鼓膜弥漫性充血透红、肿胀，向外膨出，正常标志不清，未见穿孔及分泌物。查体温39.5℃。此病若预后不良，可发生的并发症是（） ["鼓膜穿孔","中耳粘连症","鼓室硬化","慢性化脓性中耳炎","颅内并发症","颅外并发症"]
overall survey
焦炭粒度大于（）叫冶金焦。 ["25mm","40mm","50mm","80mm"]
河流生态学原则
