Based on the given process of separating substances A and B by using water and filtration, it can be inferred that substance A is likely soluble in water, while substance B is either insoluble or less soluble. This allows substance A to be dissolved in water when mixed, enabling it to be filtered out. Upon heating the remaining liquid, the water evaporates, leaving substance B behind.
Therefore, a correct statement could be: "Substance A is soluble in water, while substance B is insoluble or has low solubility in water."