He noticed the helicopter hovering over the field. Then to his astonishment, he saw a rope ladder _____ out and three men climbing down it.
B
暂无解析
耗能型缓冲的器缓冲距离为()
电击死最典型的尸体现象是:()
现行《杂物电梯监督检验规程》规定,必须由两个独立的接触器切断杂物电梯的驱动主机电源和制动器的电源
GB7588-2003《电梯制造与安装安全规范》规定,当人力操作提升装有额定载重量的轿厢所需力大于300N时,机房内应设置符合该标准要求的紧急电动运行操作装置
认定生前伤和死后伤的重要依据是:()