(B) Under PRP contracts costs other than labor costs, such as plant, machinery, and energy, make up an increased proportion of the total cost of each unit of output.
而ETS的解释中说:Choice B is incorrect because it is a natural consequence of increased worker productivity if other costs remain stable. 即如果别的成本都保持不变,那么它(应该是说b选项吧?)就是工人生产率提高的自然结果
(E) In firms in the metalworking industry where PRP contracts are in place, the average take-home pay is 15 percent higher than it is in those firms where workers have more traditional contracts.
(B) Under PRP contracts costs other than labor costs, such as plant, machinery, and energy, make up an increased proportion of the total cost of each unit of output.