uncountable and plural noun problems

[Markchoi1992]

I have just studied some grammar but I found something I was very confused.

Why some uncountable nouns contains a plural form? For example: pressure, should be an abstract noun, can be a plural noun.

In addition to this, some plural nouns, like relations, forces, affairs which are the exact the same meanings as the countable noun of them, and my question are what is this difference in or when we use plural nouns?

For example
1, I need to deal with my relation.
2. I need to deal with my relations.

1. I have pressures
2. I have pressure

Which one is correct?

 

[SoothingDave]

Some "uncountable" nouns are countable in some uses. I'm not sure why you think "pressure" is uncountable.

I'm not sure why you think "affair" and "affairs" would have the same meaning.

 

[jutfrank]

Look at it like this: The label 'uncountable' describes the use of the word in the sentence.

Uncountable nouns are always singular in form. (There may be some rare exceptions.)

If the word contains a plural 's', then you know that it can't be uncountable. So if you see the noun pressures, you know that it must be an example of a plural, and therefore countable use.

Try not to think of nouns as being always uncountable. Like I say, it depends on the use.

 

[Tdol]

Many nouns can be used countably and uncountably. Try to think of these as being flexible characteristics rather than an absolute quality of the noun.