Module 9: More About Verbs - Lesson 9.3: Infinitives

Module 9: More About Verbs - Lesson 9.3: Infinitives - 'To + Verb' Forms

Lesson 9.3: Infinitives - 'To + Verb' Forms

Welcome to Lesson 9.3! In this lesson, we will explore Infinitives. Infinitives are another type of verbal, formed with 'to + verb' (base form), and are remarkably versatile, functioning as nouns, adjectives, and adverbs within sentences. We will examine each of these functions with examples to understand the wide range of roles infinitives can play in English grammar.

Infinitives - 'To + Verb' Forms and Their Versatility:

Infinitives are verbal forms consisting of the word 'to' followed by the base form of a verb (the verb form you'd find in a dictionary entry, e.g., 'go', 'see', 'eat', 'learn', 'be'). The key characteristic of infinitives is their flexibility – they can act as different parts of speech depending on their function within a sentence.

Functions of Infinitives - Noun, Adjective, and Adverb Roles:

Infinitives are quite versatile and can play three main grammatical roles:

Infinitive as Noun:
When an infinitive functions as a noun, it can take on typical noun roles in a sentence: subject, object, or complement. In these cases, the infinitive phrase refers to an action or state as a general concept or thing.

Noun Functions of Infinitives:
- Subject of a Verb: The infinitive phrase is the 'thing' the sentence is about, acting as the subject. To err is human. (Infinitive 'To err' is the subject of 'is').
- Object of a Verb: The infinitive phrase receives the action of the main verb. He wants to travel around the world. (Infinitive 'to travel' is the object of 'wants').
- Complement of a Subject (Subject Complement): The infinitive phrase renames or identifies the subject, following a linking verb. His goal is to succeed in business. (Infinitive 'to succeed' is the complement of 'is', describing 'goal').
Examples - Infinitives as Nouns in Sentences:
- To learn a new language is a valuable skill. (Subject)
- To see is to believe. (Subject)
- She decided to apply for the job. (Object of verb 'decided')
- They want to buy a new house next year. (Object of verb 'want')
- His greatest ambition is to become a pilot. (Complement)
- The most important thing is to try your best. (Complement)
Notice how in these examples, the infinitive phrases function just like nouns - they are what the sentence is about, or what is being acted upon, or what is being described as equal to the subject.
Infinitive as Adjective:
When an infinitive acts as an adjective, it modifies a noun, providing more information about it, often indicating purpose or capability related to the noun.

Adjective Function of Infinitives: Infinitive Phrase follows the noun it modifies.

Examples - Infinitives as Adjectives:
- I need a book to read on vacation. (Infinitive 'to read' modifies 'book', specifying the *purpose* of the book).
- This is a difficult problem to solve. (Infinitive 'to solve' modifies 'problem', describing what *can be done* with the problem).
- She has a lot of work to do tonight. (Infinitive 'to do' modifies 'work', indicating *what kind* of work).
- They are looking for a house to rent in the city center. (Infinitive 'to rent' modifies 'house', describing *purpose*).
- He gave me some advice to follow. (Infinitive 'to follow' modifies 'advice', describing *what to do* with the advice).
In these sentences, the infinitive phrases function like descriptive adjectives, answering questions like "what kind of book?", "what kind of problem?", "what kind of advice?". They always come *after* the noun they are modifying.
Infinitive as Adverb:
When an infinitive functions as an adverb, it modifies a verb, adjective, or another adverb, providing additional information. Infinitives used adverbially often express purpose, reason, result, or manner.

Adverb Functions of Infinitives:
- Purpose: Often answers the question "Why?". He exercised regularly to stay healthy. (Purpose of exercising is 'to stay healthy').
- Reason: Explains the cause of an action or feeling. She was happy to help her friend. (Reason for being happy is 'to help').
- Result: Indicates the outcome of an action. He studied hard, only to fail the exam. (Result of studying hard is 'only to fail').
- Modify Adjectives: Describe the extent or way an adjective applies. It is easy to learn English. (Modifies 'easy', describing *how* easy).
- Modify Verbs: Provide additional detail about the verb's action (though less common than purpose/reason). He rushed to catch the bus. (Modifies 'rushed', purpose but also manner of rushing).
Examples - Infinitives as Adverbs in Sentences:
- He is saving money to buy a new car. (Adverb of Purpose - Why is he saving? To buy a car).
- She shouted to warn everyone about the fire. (Adverb of Purpose - Why shouted? To warn).
- I was surprised to see him there. (Adverb of Reason - Why surprised? To see him there).
- They were sad to hear the news. (Adverb of Reason - Why sad? To hear the news).
- The water was cold enough to freeze. (Adverb of Result - Result of being cold enough is 'to freeze').
- This book is difficult to understand. (Adverb modifying adjective 'difficult' - extent).
- He ran quickly to win the race. (Adverb of Purpose, modifies verb 'ran').
Adverbial infinitives often provide context, motivation, or consequences related to the main action or description in the sentence.

'Bare Infinitives' - Infinitives Without 'To':

While infinitives are typically 'to + verb', there are cases where we use 'bare infinitives' - the base form of the verb without 'to'. This happens in specific grammatical structures, notably:

After Modal Verbs: (will, would, can, could, may, might, must, should). You should go. They can swim. We will see.
After certain verbs of perception: (see, hear, feel, watch, notice, etc.) when emphasizing the completion of the action. I saw him leave. We heard the bird sing. They watched the children play.
After 'let' and 'make' (in causative structures): Let me help you. She made him apologize.
After 'had better', 'would rather', 'would sooner': You had better hurry. I would rather stay home.

In these cases, although 'to' is omitted, the verb form is still considered infinitive (base form), functioning in roles similar to infinitives.

Key Features of Infinitives (Recap):

Formed with 'to + base verb': Typically consists of 'to' followed by the base form of a verb.
Versatile Functions: Can act as nouns, adjectives, or adverbs, providing a wide range of grammatical possibilities.
Bare Infinitives: In certain contexts (after modals, verbs of perception, 'let', 'make', 'had better', etc.), 'to' is omitted, but the base verb still functions as an infinitive.

Key takeaway: Infinitives are 'to + verb' forms that are highly flexible, functioning as nouns, adjectives, and adverbs. As nouns, they can be subjects, objects, or complements. As adjectives, they modify nouns. As adverbs, they modify verbs, adjectives, or adverbs, often expressing purpose, reason, or result. Bare infinitives (without 'to') are used in specific grammatical patterns. Next, we will explore Lesson 9.4: Participles - Present and Past Participles as Adjectives!