短語詞組短語land amelioration 土地改良continuous amelioration 持續(xù)改進grassland amelioration 草地改良amelioration design 改進設計quality amelioration 質(zhì)量改進amelioration operator 改進算子amelioration efficiency 改良傚果amelioration degree 改善程度cultivational amelioration 耕作土壤改良 返回 amelioration