Let's Look at the Notion of Plural for Mass Nouns

Formulating the plural for mass nouns is rather complicated, but you can get it with a little bit of practice and mastering bits of new vocabulary to help you on the way.

As we mentioned in the example we used before, you cannot count these as one butter, two butters; one milk, two milks or one smoke, two smokes, etc. Because you cannot 'count' the quantity of a mass substance which can't be divided into separate objects, mass nouns are always in the singular.

Even if the 'substance' you refer to consists of separate things, e.g.

• furniture consists of pieces of furniture
• grass consists of blades of grass
• hair consists of strands of hair
  
• wheat consists of grains of wheat

psychologically we think of these things as indivisible when we use a mass noun. Therefore, when we want to express the plural of these nouns we actually refer to the parts or divisions of the mass nouns. So it's the noun which adds the aspect of division that's counted:

• There's no milk in the fridge.   BUT NOT   There are no milks in the fridge.
• We had two cartons of milk.     BUT NOT   We had two milks yesterday.
  

Category 1) Unit nouns - these can be general (bit, piece, part) or specific (see below)

i) Sometimes the word for a container can be used as a unit noun, as in 'a cup of tea', 'a bottle of wine', 'a glass of water', etc.

ii) As with part nouns, unit nouns are linked to the mass noun expressing the substance by using the preposition 'of', as seen in the examples above.