如果形容什麼事情為crystal clear, 意思就是非常清楚，極其明白。
He's given me crystal clear instructions on how to get to the wedding.
The boss was crystal clear about what she wanted the team to do whilst she was on holiday.
另一個短語 clear as mud, 表示很難理解或令人費解。
These instructions are as clear as mud – I'm never going to be able to get this mp3 player to work!