7L－100／8型空压机曲轴主轴承采用的是（）。 ["滚动轴承","滑动轴承","推力轴承","滚子轴承"]
请指出下列各组动物中代表了脊椎动物循环系统复杂性增加顺序的一组？（） ["蟾蜍→兔→鳄→鲨鱼","鲨鱼→青蛙→鳄→兔","鲨鱼→鳄→兔→青蛙","鳄→狗→鲨鱼→蟾蜍"]
Bags are usually stowed in between the bulk grain（）. ["to ventilate the hold","to separate the cargo","to replace shifting boards","to facilitate stowage"]
脊索动物门的下列特征中，哪一种也存在于成年的被囊动物（尾索动物亚门）中？（） ["有脊索","有鳃裂","有尾","有背侧管状神经系统"]
杆塔按用途分为哪几类？各有何特点？
试说明电力架空裸导线型号LGJ-185/25各字母、数字含义。
