The body builds up a tolerance to these chemicals. 身体形成对这些化学药品的依赖。
But if dependence-related tolerance stimulates the craving-generation system and never completely goes away, why don't former smokers continue hungering for cigarettes forever? 但如果依赖相关耐受性会刺激欲求系统且永不消失，为何以前是瘾君子的人不会一直抽菸下去呢？
