natural substance

• 天然产物

natural substance的用法和样例：

例句

1. Betulin and betulinic acid are remarkable natural products.
   白桦脂醇和白桦脂酸是非常有价值的天然产物。
2. It is difficult to set down an exact formula because cork is a natural product.
   要确定脱模剂的精确配方是困难的，因为软木是一种天然产物。