The infinitive as a non-finite form of the verb

The infinitive is a non-finite form of the verb which combines the properties of the verb with those of the noun, serving as a verbal name of a process.

Formal features of the infinitive are distinct, including its formal marker and its grammatical categories.

The formal marker of the infinitive is the particle to.

Since the use of the particle to depends on verbal environment of the infinitive, modern English has three

presentational forms of the infinitive:

- to-infinitive (the infinitive proper) which presupposes the use of the particle to in pre-position to a verb: He likes to read.

- bare infinitive which presupposes non-use of the particle to: He can read.

- split infinitive which presupposes the use of an adverb between the particle to and a verb: It is difficult to completely target that day.

In English, the infinitive can be used in three fundamentally different types of function:

- as a notional, self-positional syntactic part of the sentence, where it is grammatically free:

To be or not to be - that is the question.

- as a notional component of the compound verbal predicate, where it is grammatically semi-free:

You can always count on him.

- as a notional component of the finite conjugation of the verb, where it is grammatically bound:

to count - counted - counted

The English infinitive has three grammatical (morphological) categories: it is more than any other non-finite

form of the English verb:

- the aspective category of development (progressive aspect) which opposes continuous and non-continuous forms;

- the aspective category of retrospective coordination (perfective aspect) which opposes perfect and non-perfect forms;

- the category of voice which opposes passive and non-passive forms.