That means there's no waiting for chemical reactions to take place, no need to use reagents that can run out and no need to be an expert to get actionable information.
这意味着不需要等待 任何化学反应的结果 也不需要使用那些总会被耗尽的化学试剂 不需要操作者是水质检测专家 就能获得很有价值的信息