a.

1. 坚持不懈的；固执的
2. 持续的，持久的
   a time of high and persistent unemployment

   一个持续的高失业率的时期

3. 反复的，不断的
4. 【植】宿存的，不落的
5. 【动】持续生存的，终身保留的

adj.

1. persisting or having a tendency to persist.
2. continuing or recurring; prolonged.
3. Botany  & Zoology  (of a part of an animal or plant, such as a horn, leaf, etc.) remaining attached instead of falling off in the normal manner.