请问~不可数名词前可以加冠词吗?

请问~不可数名词前可以加冠词吗?

不可数名词前可加定冠词the,但在以下情况下：１．当其上文提到过,如：There is some water in the glass. The water is clean. 2. 当其被介词短语或定语从句修饰时,如：The water in the glass is clean. The bread you bought yesterday goes worse.