How to match uncountable nouns with predicate verbs I'm sorry to ask~

How to match uncountable nouns with predicate verbs I'm sorry to ask~

Generally speaking, uncountable nouns use the singular and countable nouns use the plural
There is much water in the thermos.
But when there is a plural noun before the uncountable noun, the predicate verb is plural
Ten thousand tons of coal were produced last year.

What form does the predicate verb use when the uncountable noun is the subject?

Uncountable nouns are used as subjects and predicates are singular

In the present tense, when the subject is an uncountable noun, what is the form of the predicate verb?

Third person singular