natural bid实叫naturaladj.自然的；天然的；私生的natural storage model蓄满产流模型natural spawning site天然产卵场natural radioelements天然放射性元素Natural focus disease自然疫源性疾病natural afforestation天然造林法natural fertilization自然受精Natural enemy species天敌种类natural rights equity权利公平natural water-table天然地下水位natural strained well天然滤水井

1. Distill the essence of natural plants.
   汲取天然植物。
2. Much of the world still relies on herbs for its medicines.
   很多国家现在还主要依赖天然植物药物。