adj.持续的;坚持不懈的;持久的;坚持不渝;
例句:
They were persistent and finally completed the work.
他们坚持不懈,最终按时完成了工作.
His cough grew more persistent until it never stopped...
他咳嗽持续的时间越来越长,直到咳个不停。
a persistent problem
长期问题