要关闭聚光灯,应该选择属性浏览器中的哪种?() ["页面工具","显露器模式","聚光灯模式","桌面注释"]
甲烷传感器在回风流中机电设备硐室的进风侧的报警浓度为(),断电浓度为(),复电浓度为()。 [">=1.0%,>=1.5%,>1.0%",">=0.5%,>=0.5%,<0.5%",">=1.0%,>=1.5%,<1.0%",">=1.0%,<1.0%,>=1.5%"]
入舍鸡的产蛋率
端面比压是机械密封重要参数之一,下面说法正确的是()。 ["A、比压大、易泄漏","B、比压大、易发热磨损","C、比压小、易发热磨损","D、比压小、易泄漏"]
为了降低氢压机的启动负荷,使氢压机正常停车时卸荷,在机体外设置有()。
当泵的汽蚀余量不足,造成泵抽空时,应()。