free base

例句：

1. 1. The reaction mechanism of the free base is still not fully understood.
   游离碱的反应机理尚未完全理解。
2. 2. The free base in the soil plays a crucial role in nutrient cycling.
   土壤中的游离碱在养分循环中起着关键作用。
3. 3.The free base in the plant can be used to produce various organic compounds.
   植物中的游离碱可以用来产生各种有机化合物。