Countable and uncountable nouns

[marin123]

My task was to divide nouns into countable and uncountable/ Here is my choice:
Countable - contract, tax, dollar, discount, entrepreneur, franchise, rate, stag, firm, trademark.
Uncountable - assistance, cash, assessment, insolvency, measure, liability.

Please, correct me if I'm mistaken.

I'm confused, cause the rule - "nouns having no plural form are uncountable" seems not to work, as ALL the nouns theoretically have plural form.

[bhaisahab]

My task was to divide nouns into countable and uncountable/ Here is my choice:
Countable - contract, tax, dollar, discount, entrepreneur, franchise, rate, stag, firm, trademark.
Uncountable - assistance, cash, assessment, insolvency, measure, liability.

Please, correct me if I'm mistaken.

I'm confused, cause the rule - "nouns having no plural form are uncountable" seems not to work, as ALL the nouns theoretically have plural form.

"assessment", measure" and "liability" are countable.
Not all nouns have a plural form in normal use.