To learn or understand very little about something; to just begin to understand or learn about something — Usually used with a limiting adverb (as "only", "hardly"). 对某项事务了解或理解的很少，刚开始学习一件事情 —— 通常与一个限制副词使用（如“only”，“hardly”）使用。

  I just started learn about Greek philosophy but I’ve hardly scratched the surface
 我刚刚开始学习希腊哲学，但我才仅仅了解皮毛。