Gerunds are defined as the –ing form of a verb. They have several functions.
1. Used as subjects and complements
Skiing is my favorite sport.
Hiking can be very strenuous.
Seeing is believing
2. Used as objects following prepositions and prepositional expressions
Thanks for tending my children.
The job consists of typing, filing, and answering the phone.
3. Used as objects following certain verbs*.
The children enjoyed watching the parade.
Ms. Terrell avoided paying her taxes until it was too late.
Gerunds can sometimes take objects of their own:
Roland is afraid of making mistakes.
Sandy is considering leaving New York.
*These verbs are commonly followed by gerunds.
An infinitive is a verbal consisting of the word to plus a verb (in its simplest "stem" form) and functioning as a noun, adjective, or adverb. The term verbal indicates that an infinitive, like the other two kinds of verbals, is based on a verb and therefore expresses action or a state of being. However, the infinitive may function as a subject, direct object, subject complement, adjective, or adverb in a sentence. Although an infinitive is easy to locate because of the to + verb form, deciding what function it has in a sentence can sometimes be confusing.
* To wait seemed foolish when decisive action was required. (subject)
* Everyone wanted to go. (direct object)
* His ambition is to fly. (subject complement)
* He lacked the strength to resist. (adjective)
* We must study to learn. (adverb)
Be sure not to confuse an infinitive--a verbal consisting of to plus a verb--with a prepositional phrase beginning with to, which consists of to plus a noun or pronoun and any modifiers.
Infinitives: to fly, to draw, to become, to enter, to stand, to catch, to belong
Prepositional Phrases: to him, to the committee, to my house, to the mountains, to us, to this address
An Infinitive Phrase is a group of words consisting of an infinitive and the modifier(s) and/or (pro)noun(s) or noun phrase(s) that function as the actor(s), direct object(s), indirect object(s), or complement(s) of the action or state expressed in the infinitive, such as:
We intended to leave early.
The infinitive phrase functions as the direct object of the verb intended.
to leave (infinitive)
I have a paper to write before class.
The infinitive phrase functions as an adjective modifying paper.
to write (infinitive)
before class (prepositional phrase as adverb)
Phil agreed to give me a ride.
The infinitive phrase functions as the direct object of the verb agreed.
to give (infinitive)
me (indirect object of action expressed in infinitive)
a ride (direct object of action expressed in infinitive)
They asked me to bring some food.
The infinitive phrase functions as the direct object of the verb asked.
me (actor or "subject" of infinitive phrase)
to bring (infinitive)
some food (direct object of action expressed in infinitive)
Everyone wanted Carol to be the captain of the team.
The infinitive phrase functions as the direct object of the verb wanted.
Carol (actor or "subject" of infinitive phrase)
to be (infinitive)
the captain (subject complement for Carol, via state of being expressed in infinitive)
of the team (prepositional phrase as adjective)
Actors: In these last two examples the actor of the infinitive phrase could be roughly characterized as the "subject" of the action or state expressed in the infinitive. It is somewhat misleading to use the word subject, however, since an infinitive phrase is not a full clause with a subject and a finite verb. Also notice that when it is a pronoun, the actor appears in the objective case (me, not I, in the fourth example). Certain verbs, when they take an infinitive direct object, require an actor for the infinitive phrase; others can't have an actor. Still other verbs can go either way, as the charts below illustrate.
Verbs that take infinitive objects without agents:
Most students plan to study.
We began to learn.
They offered to pay.
They neglected to pay.
She promised to return.
In all of these examples no actor can come between the italicized main (finite) verb and the infinitive direct-object phrase.
Verbs that take infinitive objects with agents:
He reminded me to buy milk.
Their fathers advise them to study.
She forced the defendant to admit the truth.
You've convinced the director of the program to change her position.
I invite you to consider the evidence.
In all of these examples an actor is required after the italicized main (finite) verb and before the infinitive direct-object phrase.
Verbs that use either pattern:
I asked to see the records.
I asked him to show me the records.
Trent expected his group to win.
Trent expected to win.
Brenda likes to drive fast.
Brenda likes her friend to drive fast.
In all of these examples the italicized main verb can take an infinitive object with or without an actor.
Punctuation: If the infinitive is used as an adverb and is the beginning phrase in a sentence, it should be set off with a comma; otherwise, no punctuation is needed for an infinitive phrase.
* To buy a basket of flowers, John had to spend his last dollar.
* To improve your writing, you must consider your purpose and audience.
Points to remember:
1. An infinitive is a verbal consisting of the word to plus a verb; it may be used as a noun, adjective, or adverb.
2. An infinitive phrase consists of an infinitive plus modifier(s), object(s), complement(s), and/or actor(s).
3. An infinitive phrase requires a comma only if it is used as an adverb at the beginning of a sentence.
Split infinitives occur when additional words are included between to and the verb in an infinitive. Many readers find a single adverb splitting the infinitive to be acceptable, but this practice should be avoided in formal writing.
I like to on a nice day walk in the woods. * (unacceptable)
On a nice day, I like to walk in the woods. (revised)
I needed to quickly gather my personal possessions. (acceptable in informal contexts)
I needed to gather my personal possessions quickly. (revised for formal contexts)