(Verb-noun, verb-adjective, and verb-adverb)
The infinitive, derived from the Latin word infinitus, means infinity, unlimited, without end. It is, therefore, the form of the verb which is not limited by number or person.
Although the infinitive form is the general name for a verb in English grammar, the term infinitive is discriminatingly used to refer to one of the three verbals with a unique appearance and widest range of functions. Unlike both the gerund and the present participle with -ing ending, the infinitive remains the verb-stem, preceded by to, expressed or understood. When the infinitive is preceded by to, it is called a to -infinitive or “full infinitive”. (e.g. to eat, to walk). But when it is not preceded by to, it is referred to as a bare infinitive (e.g. do, say, walk). Some verbs (e.g. behold, make, let, feel, hear, please, help, watch, see, know. and bid) go with bare infinitives in the active voice.
- Let (us watch) him do it.
- I saw Joy bid you farewell.
Like participles and gerunds, the infinitive can take a direct object. (e.g. I went there to praise God.) But unlike participles, it may have a subject as though it were a true verb (e.g. The preacher told Emma to pray after the service -: Emma is the subject while after the service is an adverbial prepositional phrase, modifying the infinitive to pray.)
The infinitive can be in the present form (i.e. the present infinitive; e.g. to teach, to drink, to read) or in the perfect form (i.e. the present perfect infinitive; e.g. to have taught, to have drunk, to have read).
The infinitive, whether present or perfect, can perform the functions of any of these parts of speech: noun, verb, adjective, and adverb. The present infinitive, for instance, demonstrates these functions thus:
- as sentence subject: (e.g. To teach is to learn.)
- as direct object: (eg. Nobody wants to die.)
- as subjective complement: (e.g. Her ambition is to marry you.)
- as object complement: (e.g. We made her smile. I told her to go.)
- as object of preposition (e.g. Grace does nothing except eat.)
- as absolute phrase: (e.g. To say the least, Obi is a cheat.)
- as a noun modifier: (e.g. I have a flat to let. Have you some petrol to sell?)
- as a pronoun modifier (e.g. Do you want him to die?)
- as verb modifier: (i.e. infinitive of purpose): (e.g. I came to see you. She smiled to impress her suitor.)
- as adjective modifier: (e.g. We are ready to learn./ I was the last to speak.)
- as adverb modifier: (e.g. Emeka ran fast to escape. / Ngozi came early to work./ I worked hard to pass my exams.)
Other Structural Uses of the Infinitive (with verbs):
1. The Present Infinitive is usually preceded by verbs expressing command, feeling, desire, expectation, fear, hope, and intention.
- I am surprised to see you. I am pleased to meet you.
- We wanted to invite you. I want to see you.
- She was ordered to leave the hall.
2. The Perfect Infinitive is preceded by a verb in the present tense to indicate an action that took place before the action denoted by the verb.
- She appears to have repented.
- Eze claims to have seen God.
- Obika considers it a privilege to have talked with the governor.
3. Verbs (in the past tense) expressing unfulfilled or unrealised command, desire, fear, hope, expectation, or intention also precede the perfect infinitive.
- Wrong: I hoped to visit you.
- Correct: I hoped to have visited you (but I could not).
- Wrong: I expected to see you.
- Correct: I expected to have seen you (but I did not see you).
4. Bare infinitives come after such expressions as had rather, had better, had sooner, and would rather which indicate preference.
- You had better respect your elders.
- You had rather study than waste your time.
- I would rather wait (i.e. I would prefer to wait).