大家知道,要想使马儿更好的干活,就要按时喂草料、饮水,发现毛脏了还要给它洗洗。好好地照料它,使它身体强壮,干起活来有劲。我们对待机器也应是这样。一台机器,是由许多零件组成的。有不少零件在工作时要做相对运动,接触面要发生摩擦,从而产生零件磨 Everyone knows that in order to make the horse work better, we must feed fodder and drinking water on time and find that the hair is dirty and wash it. Take good care of it to make it strong and work hard. We should also treat this kind of machine. A machine is made up of many parts. There are many parts to do relative movement at work, friction occurs at the contact surface, resulting in part grinding