soluble

这个谜题是可解的，只要你认真思考。

The puzzle is ___soluble if you think carefully.

盐很容易溶解在温水中。

Salt is highly ___soluble in warm water.

维生素 D 可溶于脂肪，而不溶于水。

Vitamin D is ___soluble in fat rather than in water.