呃啊~~~~我作文也烂啊~~~二战一篇没练过。。。。大概就是把drill bit production全让C工厂做,C不见得会继续保证效率节省cost了,很可能cost还会上升。还有reducing the production costs of individual machine parts不一定是only way to achieve our larger goal of reducing our overall production costs吧,还有其他方法啊 比如人员啊 浪费啊 等等不一定非得是降低机器产生的cost 你凑合着看。。。我作文真的不好。。。