即使是最早的部落也有一种计算系统，哪怕不先进，也足以完成他们必须执行的任务。

Even the earliest of tribes had a system of numeration that, if not advanced, was sufficient for the tasks that they had to perform.

youdao

各种类型的线程池中一个严重的风险是线程泄漏，当从池中除去一个线程以执行一项任务，而在任务完成后该线程却没有返回池时，会发生这种情况。

A significant risk in all kinds of thread pools is thread leakage, which occurs when a thread is removed from the pool to perform a task, but is not returned to the pool when the task completes.

youdao

该模板需要完成的最后一项任务是列出每个游泳队员的事件，但执行此任务的导航有些复杂。

The last thing the template has to do is list the events for each swimmer, but the navigation to do this is a bit more complex.

youdao