natural ice天然冰naturaladj.自然的；天然的；私生的Natural rubber tube for automobile用天然橡胶管natural arc-extinguishing system自然灭弧系统Natural death with suspected cause可疑原因的自然死亡natural formation of human essence天出其精natural fibre incendiary preventer天然纤维阻燃液natural cultural heritage resources自然文化遗产资源natural gas intermittent conversion天然气间歇转化natural light in swim competinghall游泳馆比赛厅天然光环境natural resources of sports tourist天然体育旅游资源Natural Pinus tabuloeformis forests天然油松林