natural son私生子naturaladj.自然的；天然的；私生的natural language acquisition自然语言习得natural and physical product自然物质产品Natural thermal luminescence热发光natural ventilating pressure自然通风压力Natural functional vegetable天然功能性蔬菜Natural gas pipeline project天然气管道工程natural bioactive substances天然代谢产物natural Phyllostachys edulis天然毛竹林natural ecological treatment自然生态处理natural environment of China中国自然环境变化