Volcanoes and earthquakes are among the most frightening events that nature can produce.

VOA: special.2010.01.12

But smallpox was, at one time, one of the most frightening diseases on the planet.

但是天花曾经,是这个星球上最令人恐惧的疾病之一

耶鲁公开课 - 生物医学工程探索课程节选

He published many of his most frightening stories during this time.

VOA: special.2009.02.02