Infinitives are verbals, or verbs that function as other parts of speech. They do not usually have a tense, nor do they change their ending. You cannot end an infinitive with “s,” “es,” “ed” or “ing;” if these endings are present, the word is not an infinitive – it is another form of verb or verbal. While they act as verbs in rare occurrences, they most often take the form of nouns, adjectives or adverbs. Regardless of the form, they must always have another verb present in any sentence they appear. There are two types of infinitives: bare and full.
These infinitives are less commonly used as such. More often, they follow verbs that pertain to the senses (such as feel, see or hear), helping verbs (may, must or should) or following “let” or “make.” Bare infinitives are also only present when a sentence is written in active voice, which is when a sentence’s subject is also who or what performs or causes the action of the verb. Bare infinitives are considered the simple form of verbs. Consider the following examples to help recognize a bare infinitive:
Example 1: Kathy felt the bird’s heart flutter.
“Felt” is the main verb, and “flutter” is the bare infinitive. The sentence is in active voice because Kathy is the person performing the action of the verb, feeling the bird’s heart flutter.
Example 2: The security guard saw the boy leave the premises with stolen merchandise.
“Saw” is the main verb, and “leave” is the bare infinitive. The sentence uses active voice because the action of the verb, seeing the boy, is done by the subject of the verb, the security guard.
When sentences with a bare infinitive are rewritten in the passive voice, the word “to” is placed in front of the bare infinitive, which turns it into a full infinitive.
Full infinitives generally have “to” preceding the bare infinitive. When you hear someone refer to an infinitive, they are most likely referring to the full infinitive. Full infinitives function as nouns, adjectives or adverbs. Examples of the full infinitive include:
Example 3: To dance is the only thing on the budding ballerina’s mind. (The full infinitive is “to dance,” and it functions as a noun because it is the subject of the linking verb of “is.”)
Example 4: Whenever Alicia goes on a date, she brings her cell phone to use for sending an SOS message to her friend if the date goes badly. (The full infinitive is “to use,” and it functions as an adjective because it modifies “her cell phone.”)
Example 5: Jan ran across the reunion hall to give a friend who she had not seen in many years a gigantic hug. (The full infinitive is “to give,” and it functions as an adverb because it answers the question of why “Jan ran across the reunion hall.”)
Split infinitives occur when a full infinitive is used to split the word “to” from the bare infinitive. The following are examples:
While it is not always a set-in-stone grammatical rule, avoiding the use of split infinitives is usually advised. Some style guides, such as the Chicago Manual of Style, suggest that using one to form a particular emphasis or effect is acceptable. However, for professional writing it is best to avoid them. More informal pieces generally are more forgiving with the use of split infinitives. For any written piece, consult any applicable style guides if you are unsure about expectations. The Write.com style guide, for example, dictates avoiding split infinitives.
You can fix split infinitives in several ways. First, you can move the adverb to appear before or after the full infinitive. It is important to use caution when doing so because moving it to the wrong spot can alter the meaning of your sentence. Second, you can rewrite the sentence to remove the split infinitive entirely. Consider the following examples:
Example 1: Brittney jumped in her car to quickly run to the store. (“To quickly run” is a split infinitive.)
Example 2: Brittney jumped in her car quickly to run to the store. (With “quickly” preceding the infinitive, the sentence means that Brittney quickly jumped in her car.)
Example 3: Brittney jumped in her car to run to the store quickly. (With “quickly” following the infinitive, the sentence means Brittney wanted the trip to not take very long.)
Example 4: Brittney jumped in her car for a quick trip to the store. (Rewording the sentence entirely without any part of the split infinitive often provides the most clarity.)