（一）一台叶尼塞联合收割机在秋收作业中，工作一段时间后液压驱动系统油温上升较快，接着是行走速度渐缓直至不能行走。待机车稍冷后又能行驶一段距离。经检查，冷却器、回油安全阀均正常。最后拆解变量泵，发现其配流盘及衬盘（支承盘）已严重磨损，导致系统容积效率下降，? (A) a Yenisei combine harvester in the autumn harvest operation, after working for a period of time the hydraulic drive system oil temperature rose rapidly, then the walking speed is slow until it can not walk. After the locomotive is slightly cold and can drive some distance. After inspection, cooler, oil return valve are normal. Dismantling the final variable pump and found its distribution plate and the backing plate (support plate) has been severely worn, resulting in reduced system volume efficiency ,?