A verbal is the form of a verb that is used as a different part of speech. Participles can either be past participles or present participles and they act as an adjective.
Gerunds always act as a noun.
Infinitives in a sentence may act as a noun, an adjective, or an adverb. A verbal phrase is a phrase consisting of a verbal plus any complements or the verbal plus any modifiers to the verbal or the complement. For more see the glossary entry on each individual verbal type. English Plus, All rights reserved.