English sentences have generally only one verb, but they may have several verbal phrases. Verbal phrases are constructed from the infinitive, present participle, or past participle and their corresponding complements:
["to" <Vinf> [<complement>]] [<Ving> [<complement>]] [<Vpastp> [<complement>]]
Infinitive and present participle verbal phrases may take the place of nouns. Present participle phrases used as nouns are also called gerund phrases. Infinitive verbal phrases are also used as adverbs. Present participle and past participle verbal phrases may act like adjectives. In this case, they are also called participial phrases. Verbal phrases that are not essential to the meaning of the sentence are separated by commas.
John agreed to run for president.
To write was his ambition.
The man stopped to rest.
Reading books in the train gives me a headache.
Buildings constructed during the depression are substandard.
Students drinking on campus will be expelled.
Trembling with excitement, Mary waited for her friend.
The house, remodeled recently, is very attractive.