Identify the sentence structure.

Fred came running toward them.

simple

compound

complex

compound-complex

That is a simple sentence, it has only a simple subject, pronoun and a verb.

:D

Your answer would be that the sentence above is a simple sentence.

Explanation:

The sentence above is a simple sentence. A simple sentence in grammar has only one main or independent clause and no dependent or subordinate clauses. As you can see, the NP Fred is the subject of the sentence and the VP came running toward them is the verbal predicate. This sentence one independent clause and no subordinate clauses.

An independent clause is a clause that can form a complete sentence standing alone, having a subject and a predicate.