natural age自然年龄naturaladj.自然的；天然的；私生的natural chronic Keshan disease自然慢型克山病natural colour animal hair rug天然色动物毛地毯natural antibactenial immunity天然抗菌免疫Natural boundary of a function函数的自然边界natural ecological circulation自然生态循环natural drinking mineral water天然饮用矿泉水natural language expert system自然语言专家系统natural language symbol string[计] 自然语言符号串natural capital stock accounts自然资本存量帐户Natural gamma spectrum logging自然伽马能谱测井