分叙接触式、光电式断头自停装置的作用原理及其优缺点。
During maneuvering operations for a direct reversing large, low-speed, main propulsion diesel engine, which of the following actions is used to stop the shaft from turning prior to reversing the engine rotation?（） ["Flywheel inertia","Admission of starting air","The way of the vessel","securing of fuel to the cylinder"]
自我评价的运用可体现在以下几个方面（）。 ["家长评价问卷","建立幼儿发展档案","对照计划进行评价","教师自我评价问卷"]
空压机起动前为什么要打开卸荷阀及放空阀？
下图中细胞器P的最重要的功能是：（） ["合成蛋白质","利用异化作用所产生的能量合成ATP","利用日光能合成ATP","转运蛋白质"]
电力通信网采用了哪些新技术？
