Onions are biennials; their life cycle is two years long.

VOA: special.2011.06.28

Cells can stop in their lifetime at some point in the cell cycle and persist for long periods of time.

细胞生命期可以停止在细胞周期的某个点,并保持很长时间

耶鲁公开课 - 生物医学工程探索课程节选

Here is the pitch in--of--a string an octave higher so you can see it this way. As you probably know, if you take a long string and pluck it, it's going to take that long string a long time to pass that sort of cycle, if you will, just one pass through that cycle.

这也是个音高,一个高八度的音弦,你可以这样这样看 你们可能知道,如果你拨动长弦,长弦要经过很长时间,才能完成一个震动周期,如果你想,可以尝试下

耶鲁公开课 - 聆听音乐课程节选

Galmudug regional government Minister of Planning Omar Mohamud warns that not implementing a long-term solution to the water problem will fuel the vicious cycle of droughts, hunger,and violence and keep the Somali people in the iron grip of poverty.

VOA: standard.2009.10.06