It is true that the cost of maintenance of idle plant may often, for the reasons given above, reduce the magnitude of marginal user cost, especially in a slump which is expected to last a long time.

的确，出于上述原因，闲置工厂的维护成本通常会降低边际用户成本的幅度，尤其是在预计会持续很长时间的低迷时期。