The queueing system imposes an important exception to this rule with a priority class.

这个排队系统在 prioirty 类（class）上增加了重要的规则。

youdao

Each thread maintains exception handlers, a scheduling priority, and a set of structures the system USES to save the thread context until it is scheduled.

每个线程都维护异常处理程序、调度优先级和一组系统用于在调度该线程前保存线程上下文的结构。

youdao

Timed activation and profile lock rules are an exception and have the topmost priority, which cannot be changed.

定时启动和配置文件锁定规则是一个例外，并有最高优先事项，这不能改变的。

youdao

Yet until now, with the exception of narcotics, illicit trade has simply not been a priority in international law and treaty making, or in international police work and cooperative law enforcement.

NPR: Tracking the World's Black Market: 'Illicit'