Another expression linked to sailing is batten down the hatches.

VOA: special.2009.05.24

But you can write it down It's a concept that links itself to a literary or verbal written expression.

但是你们可以将负二的平方用笔写下来,那是种概念，能将其自身,与文学或文字书面的表达连接起来。

麻省理工公开课 - 电影哲学课程节选

Today we tell about the expression "down to earth."

VOA: special.2009.03.08