Infinitives, Participles, and Gerunds
Infinitives, gerunds, and participles are closely related to verbs, so first recall what verbs are.
Verbs are conjugated (they show tense or time) and, when joined with a subject, form a clause.
example: The lion hunted the antelope. Hunted is the verb in an independent clause.
example: After the female lion moved onto the plain, she hunted antelope. Moved is the verb of the dependent clause and hunted the verb in the independent clause.
example: To hunt antelope was the lion's main desire. Here the infinitive phrase functions as a noun and subject.
example: To hunt antelope, the lion first hid in the tall grass. Here the infinitive phrase functions as an adverb. Remember, adverbs indicate where, when, why, or how.
example: The best way to hunt antelope depends on the season. Here the infinitive phrase functions as an adjective (to hunt antelope modifies way).
example: Hunting antelope, the lion fed herself and her cubs. The present participial phrase Hunting antelope modifies lion and is an adjective.
example: The lions hunting on the plains did not reduce antelope numbers. The present participial phrase hunting on the plains modifies lions and is an adjective.
example: The hunting lion focuses on her prey. Hunting is a present participle functioning as an adjective.
example: The lions will be hunting antelope. Hunting is a present participle functioning as part of the main verb will be hunting.
example: Hunting antelope can be difficult. The gerund hunting is a noun. The gerund phrase Hunting antelope is the subject of the sentence.
Like other nouns, gerunds can serve as subjects, direct objects and objects of prepositional phrases. See gerunds.
example: Hunted by lions, the antelope scattered into the trees. The past participle hunted is part of a phrase that modifies antelope. It's an adjective.
example: The hunted antelope scattered into the trees. Here the past participle is a one-word adjective.
example: The lions have hunted antelope. The past participle hunted is part of the main verb (have hunted).
example: The antelope will be hunted. The past participle hunted can be considered part of a passive verb or an adjective (better to consider it part of the transitive passive verb will be hunted so that you recognize the transitive active verb).
example: The antelope that was hunted today was male. The dependent clause that was hunted today can be simplified to the past participle phrase hunted today: The antelope hunted today was male.