在这些项目中的进程和线程中常常出现并行。

Concurrency appears in processes and threads most often in these projects.

youdao

但是问题常常出现。

All too often, however, problems arise.

youdao

由于此地离北极如此之近，北极光在这里常常出现。

The northern lights are often visible here because it is so close to the North Pole.

youdao

And increasingly you'll actually see this written in the New York Times or used in politics.

这个词常常出现在纽约时报,或政治领域中。

耶鲁公开课 - 新约课程节选