递降

chéng běn zhú jiàn dì jiàng

成本逐渐递降。

Costs are gradually falling.

gǎi jìn gōng yì shǐ yuán cái liào de xiāo hào zhú yuè dì jiàng

改进工艺，使原材料的消耗逐月递降。

Reduce the consumption of the raw materials month after month through improving the craftsmanship.