我们在山湖中游泳，水非常清澈。

We swam in the ___crystal ___clear water of the mountain lake.

浅海的水非常清澈，非常适合浮潜。

The shallow sea had ___crystal ___clear water, perfect for snorkeling.

她的指示非常清晰，所以每个人都立即明白了。

Her instructions were ___crystal ___clear, so everyone understood immediately.