envelope delay tracer

例句：

1. 1.The envelope delay tracer is used to detect the presence of a virus in a sample.
   信封延迟追踪器用于检测样本中是否存在病毒。
2. 2.The tracer was designed to help researchers identify the source of the pollution.
   该追踪器旨在帮助研究人员确定污染的来源。
3. 3.The delay tracer helped us to understand the impact of the event on the system.
   延迟追踪器帮助我们理解了该事件对系统的影响。