First sentence has c: no infinitive
I have never seen an eagle soar.
Second sentence is c. to come from the
Native Americans
The name "Yellowstone" is thought to come from
the Native Americans who named the area for its yellow cliffs.
Infinitive phrases starts with
infinitives that is, “to” added by a simple verb and can be used as nouns,
adjectives or adverbs. In the case of including a main clause in the sentence,
infinitive phrase separates it with comma.