He is running.
This sentence pattern is subject-verb, or subject-linking verb-subject structure?
He is running.
This sentence pattern is subject-verb, or subject-linking verb-subject structure?
He is running.
The choice of analysis depends on how detailed you want it to be.
In very simple terms, it consists of two constituents: the subject "he" and the predicate verb phrase "is running".
A more detailed (and advanced) analysis shows it to be subject-verb-subordinate clause, where the verb "running" forms a clause serving as complement of the main verb "is".