The subject in a sentence or clause is the person or thing doing, performing, or controlling the action of the verb.
Every sentence requires a subject and a verb to be complete. Without a subject, we would have an action being done by no one or nothing—simply happening on its own, which cannot happen. (The only exception to this is in imperative sentences, in which the subject is implied, as in: “Do your homework!”)
Only that which has the grammatical function of a noun can be the subject of a clause. This is because it is someone or something that is capable of performing or “controlling” the action of the verb. This function can be performed by each of the following:
Type of Subject
“Computers can process numbers very quickly.”
“A boy I know owns a motorcycle.”
“Someone ate this cake!”
“Swimming is great exercise.”
“Traveling the world has been my lifelong dream.”
“To err is human; to forgive is divine.”
“To fall in love can be both wonderful and tragic.”
“Whoever knows the truth should come forward.”
“There is nothing we can do for him now.”
As we can see in the above examples, the subject most typically occurs at or near the beginning of a clause, preceding the main verb that describes the action of the clause (known as the finite verb).
When auxiliary verbs are used to make questions (interrogative sentences) without question words, then the subject comes between the auxiliary verb and the main verb. For example:
- “Is hiking your favorite activity?”
- “Did Mary come by yesterday?”
- “Have you heard this song before?”
The examples we’ve seen so far have been of sentences in the active voice, meaning the subject of a clause or sentence is also the agent of the verb’s action.
Sentences in the passive voice, however, create a bit of confusion. Structurally, the object of the verb’s action becomes the grammatical subject of the clause, while the “proper” subject (the agent of the action) becomes modifying information. For example:
- “Jack is reading the book.” (active voice)
- “The book is being read by Jack.” (passive voice)
- In the first sentence, Jack is both the subject of the sentence and the agent of the verb is reading.
In the second sentence, though, the book is now the subject of the sentence. The agent of the verb’s action, Jack, becomes the object of the prepositional phrase by Jack, which modifies the verb is being read.
Subject-verb agreement refers to using certain conjugations of verbs with singular subjects and different conjugations with plural subjects. This happens most noticeably with the verb to be, which becomes is or was with singular subject nouns and are or were with plural subjects.
- “My brother is back from college.” (singular present simple tense)
- “The company was in financial trouble.” (singular past simple tense)
- “Many people are frustrated with the government.” (plural present simple tense)
- “The computers were rather old.” (plural past simple tense)
For any other verb, we only need to make a change if it is in the present simple tense. For most verbs, this is accomplished by adding an “-s” to the end if it is singular and leaving it in its base form if it is plural. For example:
- “My father runs his own business.” (singular)
- “But his sons run it when he’s away.” (plural)
- “The dog wags his tail when he is happy.” (singular)
- “Dogs sometimes wag their tails when they’re angry or scared.” (plural)
The verbs have and do also only conjugate for singular subjects in the present simple tense, but they have irregular forms for this: has and does. For example:
- “The apple has a mark on it.” (singular)
- “All the apples have marks on them.” (plural)
- “My teacher does not think it’s a good idea.” (singular)
- “The other teachers do not mind, though.” (plural)
Finally, the modal auxiliary verbs (will, would, shall, should, can, could, might, must, and ought to) do not conjugate for singular or plural subjects—they always remain the same. For instance:
- “This phone can also surf the Internet!” (singular)
- “Most phones can do that now.” (plural)
- “The president will arrive in Malta next week.” (singular)
- “The other diplomats will arrive shortly after that.” (plural)
Pronouns stand in for a person or thing we are speaking about or referring to; they are used to avoid repetition in speech or writing. The personal pronouns in the subjective case—I, you, he, she, it, we, and they—can act as substitutes for the subject of the clause or sentence. In this instance, they are known as subject pronouns. For example:
- “John is running late, but he is almost ready.” (The pronoun he, replaces the noun John in the clause he is almost ready.)
- “The book is on the table. It is just over there.” (The book is a non-person noun, so it can be substituted with the pronoun it in subsequent clauses or sentences.)
The question words who and what can also act as subject pronouns of the sentence or clause. For example:
- “Who is going to the party later?”
- “What just happened?”
(These form what are known as subject questions; we’ll look at these a little more in depth later on.)
There are other pronouns in English that can act as the subjects of clauses or sentences. Indefinite pronouns, for example, are used in place of nouns without specifying a particular person or thing that is being represented, as in:
- “Everyone is waiting for the party to begin.” (The action of waiting is being done by everyone.”
- “I have five teachers, but only one is writing me a recommendation.” (The action of writing is being done by one.)
- “Nobody told me about this.” (The action of told was done by nobody.)
Common Subject Errors
Because the subject can be so widely varied in English, a number of errors can arise about how to correctly use (or not use) a subject in a sentence. Let’s look at some common errors that occur.
Subject-Verb Agreement Errors
Unfortunately, there are many opportunities for confusion as to when to omit the “-s” when conjugating a verb for subject-verb agreement. Remember: we only need the “-s” when using the present simple tense in affirmative (non-negative) sentences, and when using subjects that are in the third person.
- “I live in Paris.” (correct)
- “I lives in Paris.” (incorrect)
- “You live in Paris.” (correct)
- “You lives in Paris.” (incorrect)
- “He lives in Paris.” (correct)
- “He live in Paris.” (incorrect)
Here are some other examples of subject-verb errors with third-person singular and third-person plural:
- “People live here.” (correct)
- “People lives here.” (incorrect)
- “The children are playing outside.” (correct)
- “The children is playing outside.” (incorrect)
A person (singular) lives, while people (plural) live; a child (singular) is playing, while children (plural) are playing. We can have “one person” or “one child,” but we have “two/three/10/many people or children.”
These are known as irregular plurals because they do not follow the normal rule of making a noun plural by adding an “-s” or “-es” to the end. Nevertheless, they still require the correct third-person verb conjugations, as with any other noun.
(See the chapter on Plurals to learn more about the spelling rules for regular and irregular plurals.)
Indefinite pronouns can sometimes cause confusion because many seem to be referring to a group of people or things, and so should take third-person plural verbs, when in fact they require third-person singular verbs. For example:
- “Everyone has a television.” (correct)
- “Everyone have a television.” (incorrect)
The indefinite pronoun everyone refers to “each single person.” It does not refer to a group, but instead to separate individuals, so it therefore requires a third-person singular verb. Other examples that take third-person singular verbs include no one/nobody, someone/somebody, and anyone/anybody.
Other indefinite pronouns use qualifying information that can make subject-verb agreement confusing. For example:
- “One of my students has gone to England.” (correct)
- “One of my students have gone to England.” (incorrect)
In instances like this, the auxiliary verb have should be conjugated with the indefinite pronoun one (singular) instead of students (plural)—one is functioning as the subject of the sentence, while of my students is an adjectival prepositional phrase that describes it.
Here’s a similar example:
- “Each person studies individually.” (correct)
- “Each person study individually.” (incorrect)
Because each is paired with the word person, which it modifies, it implies a group of people. However, like one, this subject has to take a third-person singular verb.
Double Subject Error
We must be careful to avoid using a pronoun as a “double” subject in the same clause—we only use a pronoun as a subject when it refers to the subject in a different clause.
- “My brother speaks English.” (correct)
- “He speaks English.” (correct)
- “My brother he speaks English.” (incorrect)
- “My country is very beautiful.” (correct)
- “It is very beautiful.” (correct)
- “My country it is very beautiful.” (incorrect)
- “My car cost me a lot of money.” (correct)
- “This cost me a lot of money.” (correct)
- “This my car cost me a lot of money.” (incorrect)
Omission of the subject
We occasionally use what’s known as a “dummy pronoun” to function as a subject in a clause. The two dummy pronouns in English are there and it, and they do not have antecedents the way proper pronouns do. Because they don’t refer to a concrete element semantically, it can seem like they should be omitted in certain circumstances, but we must be careful to always include them where necessary. For example:
- “I think it is going to rain.” (correct)
- “I think is going to rain.” (incorrect)
In the first example, there is no subject before is. We always need a subject before the verb. When we talk about the weather, time, speed, distance, or things, we use the dummy pronoun it as the subject of the clause.
Here is another example of this kind of error:
- “Is there anything I can help you with?” (correct)
- “Is anything I can help you with?” (incorrect)
In the first example, we do not know what the speaker wants to help with, because there is no subject. In this case, we use there as the subject to make the sentence complete.
Subject before auxiliary verbs in questions
When we form questions, the subject of the sentence still comes before the main verb. However, if an auxiliary verb is being used to create the question, it’s also important to remember that the subject comes after the auxiliary verb. For instance:
- “Where does Mary work?” (correct)
- “Where does work Mary?” (incorrect)
- “Where Mary does work?” (incorrect)
- “Do you speak English?” (correct)
- “You do speak English?” (incorrect)
Subject Question Error
In a “subject question,” in which the subject is implied by the question, we do not usually add the auxiliary verb do in the same way as in normal questions. For instance:
- “What did happen last night?” (less common; only used for emphasis when trying to determine what did happen vs. what did not happen)
- “What happened last night?” (much more common)
Since the subject is already in the question, we do not have to use an auxiliary verb.
When we use a subject question in the past simple tense, the verb needs to be used in the past tense too. This is because the auxiliary verb did, the past tense of do, is absent.
Normal Questions vs. Subject Questions
To better understand this, let’s look at a comparison between a normal question and a subject question.
First, let’s look at two statements:
- A) I saw Mary.
- B) Anne saw me.
If we were asking a question to which sentence A was the answer, it would be a normal question:
- “Who did you see?”
- “I saw Mary.”
The subject in the normal question, you, corresponds to the subject in the answer, I. Since this is a normal question, we use the auxiliary verb, did, to form the past tense of the main verb, see.
If we were asking a question to which sentence B was the answer, it would be a subject question:
- “Who saw you?”
- “Anne saw me.”
Here, who, the question word, is what corresponds to the subject in the response, Anne. You is the direct object of the verb saw, which is put in the past tense because we do not use the auxiliary verb did; it corresponds to me in the response, which is also the direct object of saw.