built-in contaminants

• 内含的杂质

built-in contaminants的用法和样例：

例句

1. Active carbon adsorbs poisonous gases and impurities in liquids.
   活性炭吸附毒气和液体中的杂质。
2. The oxygen reacts vigorously with the impurity in the iron.
   氧气与铁中的杂质发生剧烈的化学反应。