Which statement about immersion suits is TRUE?（） ["The primary color of the suit's exterior may be red，orange or yellow","The suit must，without assistance，turn an unconscious person's mouth clear of the water within 5 seconds","The suit is flameproof and provides protection to a wearer swimming in burning oil","The suit may be stored in a machinery space where the ambient temperature is 160°F"]
手抬机动消防泵的汽油发动机有四冲程汽油机和二冲程汽油机两种。
公共管理实质上是对政治权威的管理。（）
依据华电集团《电力安全工作规程》（电气部分）规定哪些工作需填用电气第一种工作票？
只要离心泵启动，则活塞引水泵的排气引水可自动进行，还要进行单独的引水操作。
简要说明MPLS网络的结构。
