- The nouns in which the opposition of explicit discreteness/ indiscreteness is expressed : cat::cats;
- The nouns in which this opposition is not expressed explicitly but is revealed by syntactical and lexical correlation in the context. There are two groups here:
- Singularia tantum. It covers different groups of nouns: proper names, abstract nouns, material nouns, collective nouns;
- Pluralia tantum. It covers the names of objects consisting of several parts (jeans), names of sciences (mathematics), names of diseases, games, etc.
3.The nouns with homogenous number forms. The number opposition here is not expressed formally but is revealed only lexically and syntactically in the context