Both of the following sentences are consistent with how most educated Americans used the English language between the years 1990 and 2020:
- We don’t use "the" with plural nouns when we are referring to things in general.
- We don’t use "the" with plural nouns when we refer to things in general.
Both sentences are correct.
An alignment is shown below to show what the differences between the two sentences are:
+----------------------------------------------+---------------+-----------------------+
| We don’t use "the" with plural nouns when we | are referring | to things in general. |
+----------------------------------------------+---------------+-----------------------+
| We don’t use "the" with plural nouns when we | refer | to things in general. |
+----------------------------------------------+---------------+-----------------------+
There exist sentences such that the word "refer" is interchangeable with the phrase "are referring" within that sentence while preserving grammatical correctness and meaning.