natural gas天然气naturaladj.自然的；天然的；私生的natural finish tile不上釉的瓷砖natural classifying自由分类natural bone tissue天然骨组织natural attapulgite天然凹凸棒石natural insecticide生物源杀虫剂natural refrigerant天然制冷剂natural restoration自然恢复natural obligations[法] 自然债natural goods value自然物价值Natural moxibustion天灸