Explain the concept of infinitive nouns and their usage.

Infinitive nouns are nouns that are formed from the base form of a verb by adding the word "to" before the verb. They are called infinitive nouns because they retain the basic meaning of the verb while functioning as a noun in a sentence.

The usage of infinitive nouns can be categorized into three main functions: as subjects, as objects, and as complements.

Firstly, infinitive nouns can be used as subjects in a sentence. In this case, they act as the main focus of the sentence and answer the question "What is happening?" or "What is being done?". For example, in the sentence "To swim is my favorite hobby," the infinitive noun "to swim" functions as the subject of the sentence, indicating the action or activity that is the speaker's favorite hobby.

Secondly, infinitive nouns can be used as objects in a sentence. They receive the action of the verb and answer the question "What is being done?". For instance, in the sentence "I want to learn French," the infinitive noun "to learn" acts as the direct object of the verb "want," indicating the action that the speaker desires to perform.

Lastly, infinitive nouns can be used as complements in a sentence. They provide additional information about the subject or object of a sentence. For example, in the sentence "Her dream is to become a doctor," the infinitive noun "to become" functions as the complement of the subject "her dream," describing the desired outcome or goal.

It is important to note that infinitive nouns can also be modified by adverbs or other words to provide more specific information. For instance, in the sentence "He decided to quickly finish his homework," the adverb "quickly" modifies the infinitive noun "to finish," indicating the manner in which the action is performed.

In summary, infinitive nouns are formed by adding "to" before a verb and can be used as subjects, objects, or complements in a sentence. They retain the basic meaning of the verb while functioning as nouns, and their usage depends on the specific role they play in the sentence.