What is a Sentence?
At its most basic level, a sentence is a sequence of words that conveys a complete
thought, formed by a subject (what the sentence is about, generally the noun or pronoun
that is the focus of the action in a sentence) and a predicate (the verb plus any other
information).
The rule outlining the components of a sentence, therefore, is as follows:
Subject + Predicate = Sentence
Understanding what a sentence does can help you write clearer sentences.
Subjects
The subject of a sentence is the sentence topic (what a sentence is about).
Subjects come in five varieties:
1)
2)
3)
4)
5)
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Nouns
Pronouns
Noun clauses
Infinitives
Gerunds
Nouns
Nouns are people, places, ideas, concepts, and things.
o They can be singular (e.g., child) or plural (e.g., children).
o Sentences can have multiple nouns, but the subject noun is the focus of the
sentence. Essentially, it is the “star” of a sentence.
Following is an example of a noun used as the subject of a sentence:
Islam is a world religion.

Pronouns
A pronoun takes the place of a noun to simplify a sentence.
o Pronouns include words like he, she, it, I, we, you, they, one, her, him, and
them.
Without pronouns, sentences would look like this:
The lab assistant records the lab assistant's findings hourly. The lab
assistant puts the records in the lab assistant’s folder, so that the lab
assistant’s supervisor can check the records.
© The Writing Centre, Saint Mary’s University, 2012
This handout is for personal use only. Reproduction prohibited without permission.
What is a Sentence
2
With pronouns, reading becomes easier and less repetitive:
The lab assistant records her findings hourly. She puts the records in her
folder, so that her supervisor can check them.
Following is an example of a pronoun used as the subject of a sentence:
He was also recognized as a prophet.

Noun clauses
A noun clause is a group of words that acts as a noun. When examined by
themselves, noun clauses can look like mini-sentences (although not
complete sentences) because they contain both a subject and a predicate.
o When used as the subject of a sentence, a noun clause usually begins with
one of the following words: that, how, when, what, where, why, and
whether.
Consider the following examples:
What the researcher said was controversial.
That the research was controversial is an understatement.
How the research was conducted appears to be the problem.
o Note that the noun clause, underlined in each example, is followed by a
verb, which helps to complete the sentence.
o Also note that even though some of the noun clauses begin with "question
words" (such as what), the sentences are not questions. They are
statements.

Infinitives
An infinitive is the to form of a verb.
o When placed at the beginning of a sentence, an infinitive is used as a
subject.
For example:
To study is to be diligent.
o Notice that when infinitives are used as subjects, sentences often sound
formal or philosophical.
© The Writing Centre, Saint Mary’s University, 2012
This handout is for personal use only. Reproduction prohibited without permission.
What is a Sentence

3
Gerunds
A gerund is the -ing form of a verb.
o When used as a subject, a gerund is located at the beginning of a sentence.
Fencing became a popular sport in fifteenth century Spain.
o Note that the gerund (fencing) stands on its own as the subject, with the
sentence's main verb (became) immediately following the gerund.
Predicates
Predicates contain a verb, as well as any additional information used to describe a
situation.
Consider the following examples:
This particular species thrives.
This particular species thrives in temperate, deciduous forests.
o The predicate (underlined) in each example completes the sentence, where
the first example contains only a verb (thrives), and the second example
contains a verb and additional information (where the species thrives).
The one (and only) exception to the rule
The rule described at the beginning of this handout (a subject + a predicate = a sentence)
has one exception: Sentences in the command form do not require subjects.
o In commands (i.e., the imperative voice), the subject of a sentence is often
hidden within the predicate. The subject is hidden because it is implied.
Consider the following examples:
State your name for the record.
Study both the textbook and class notes for the exam.
Recycle!
o In each example, the implied subject is you. For example, the first
example could be reworded to read "You must state your name for the
record."
© The Writing Centre, Saint Mary’s University, 2012
This handout is for personal use only. Reproduction prohibited without permission.