Components of a Sentence: Identifying the Sentence Core

Every language has its own sentence structure and rules for what is included. Word order is particularly important in English grammar. The basic structure of sentences in English is S-V-O, or subject-verb-object. This means that, in most cases, the subject always appears before the verb. We will address the object in the next section.

Clearly written, complete sentences require key information: a subject, a verb, and a complete idea. (Some verbs (transitive verbs) require an object (O), and some verbs (intransitive verbs) don’t to make a complete idea. Most verbs are transitive. A sentence needs to make sense on its own. Sometimes, complete sentences are also called independent clauses. A clause is a group of words that may make up a sentence. An independent clause is a group of words that may stand alone as a complete, grammatically correct thought. The following sentence has three independent clauses (in brackets).

  • [We went to the store,] [we bought the ingredients on our list,] and then [we went home].

All complete sentences have at least one independent clause. You can identify an independent clause by reading it on its own and looking for the subject and the verb.


The video linked below explains the basics of sentence structure.

English Sentence Structure. by Oxford Online English. License: All Rights Reserved. License Terms: Standard YouTube License.

Identifying the Verb

Types of Verbs

It may be easiest to first identify the verb in a sentence even though it generally appears after a subject. A verb is often an action word that shows what the subject is doing. A verb can also link the subject to a describing word. There are three types of verbs that you can use in a sentence: action verbs, linking verbs, or helping verbs.


The printed words "verb pure verb." A wedding ring laid on the page circles the words "pure verb."
Image 8.1 (Credit:“Pure Verb” by Rebecca Siegel on flickr is licensed CC BY 2.0.)

Action Verbs

A verb that connects the subject to an action is called an action verb. An action verb answers the question what is the subject doing? In the following sentences, the bold words are action verbs.

Example 1

The dog barked at the jogger.
He gave a short speech before we ate.

Linking Verbs

A verb can often connect the subject of the sentence to a describing word. This type of verb is called a linking verb because it links the subject to a describing word. In the following sentences, the bold words are linking verbs.

Example 2

The coat was old and dirty.
The clock seemed broken.

If you have trouble telling the difference between action verbs and linking verbs, remember that an action verb shows that the subject is doing something, whereas a linking verb simply connects the subject to another word that describes or modifies the subject. A few verbs can be used as either action verbs or linking verbs.

Example 3

Action verb: The boy looked for his glove.
Linking verb: The boy looked tired.

Helping Verbs

A third type of verb you may use as you write is a helping verb. Helping verbs are verbs that are used with the main verb to describe a mood or tense. Helping verbs are usually a form of be, do, or have. The word can is also used as a helping verb.

Example 4

The restaurant is known for its variety of dishes.
We have seen that movie three times.

Exercise 1: Copy each sentence onto your own sheet of paper and underline the verb(s) twice. Name the type of verb(s) used in the sentence in the space provided (LV, HV, or V).

  1. The cat sounds ready to come back inside. ________
  2. We have not eaten dinner yet. ________
  3. It took four people to move the broken-down car. ________
  4. The book was filled with notes from class. ________
  5. We walked from room to room, inspecting for damages. ________
  6. Harold was expecting a package in the mail. ________
  7. The clothes still felt damp even though they had been through the dryer twice. ________
  8. The teacher who runs the studio is often praised for their restoration work on old masterpieces. ________.

The Time Test

If you need to identify the verb in a subject, you can apply the time test, which is:

  1. Changing the tense of the sentences
  2. Observing which words change. The words that change are the verbs.

Example 5

Present tense: Dax, my German Shepherd, loves to run at the beach.

Past tense: Dax, my German Shepherd, loved to run at the beach.

We can see that “loves” changed to “loved,” so “loves” is the verb in the original sentence.

In college classes, though, we tend to write more complicated sentences than this. There may be more than one subject and/or verb, the subject may be compound, or it may be embedded into a pronoun. Verbal phrases (which can easily be confused with verbs) may also add description in a sentence. How to tell what the verb is? Apply the time test! See the examples below for more practice finding the verb.

Example 6

Present tense: Hauling a load of wood, the truck overturns and wood flies everywhere.

Past tense: Hauling a load of wood, the truck overturned and wood flew everywhere.

  • The verbs are “overturns” and “flies.”

Present (progressive) tense: I am hurrying around the house, trying to gather everything I need before I have to catch my plane.

Past tense: I hurried around the house, trying to gather everything I needed before I had to catch my plane.

  • The verbs are “am hurrying,” “need,” and “have.”

Past/past progressive: My friend, whom I have known for fifteen years, was very supportive during this time.

Future/future progressive: My friend, whom I will have known for fifteen years, will be very supportive during this time.

  • The verbs are “have known” and “was”. Notice that, in this case, the subject and the verb are separated by an intervening descriptive clause with commas around it.

Past tense: Daria and Oswaldo played hockey.

Present tense: Daria and Oswaldo play hockey.

  • The verb is “played.”

Identifying subjects

The word "subject" lit up in neon against a black background.
Image 8.2 (Credit “SUBJECT” by Luca Pedrotti on flickr is licensed CC BY-NC 2.0.)

When you read a sentence, you may first look for the subject, or what the sentence is about. The subject, or what the sentence is about, usually appears at the beginning of a sentence as a noun or a pronoun. A noun is a word that identifies a person, place, thing, or idea. A pronoun is a word that replaces a noun. Common pronouns are I, he, she, it, you, they, and we. In the following sentences, the subject is underlined once.

Example 7

Malik is the project manager for this project. He will give us our assignments.

  • In these sentences, the subject is a person: Malik. The pronoun He replaces and refers back to Malik.

The computer lab is where we will work. It will be open twenty-four hours a day.

  • In the first sentence, the subject is a place: computer lab. In the second sentence, the pronoun It substitutes for computer lab as the subject.

The project will run for three weeks. It will have a quick turnaround.

    • In the first sentence, the subject is a thing: project. In the second sentence, the pronoun It stands in for the project.

Once you have identified the verb, you can easily identify the subject by asking, “who or what does the verb?”Sometimes, the subject may be compound (more than one), and sometimes, the subject may be separated from the verb. The following examples refer to the example sentences in the time test, above.

Example 8

Who loves to run at the beach? Dax does.

  • Dax is the subject of the sentence.

What was hauling a load of wood? What flew everywhere?

  • The truck and wood are the subjects in the sentences.

Who was hurrying around the house? Who was gathering everything they needed? Who needed to catch a plane?

  • The subject of each of these is “I,” but notice there are three “I”s in the original sentence, so each of them would be a subject.

Who was very supportive? Who has known the friend?

  • My friend” and “I” are the subjects. This one is tricky because of the construction of the original sentence. There are actually two clauses (subject-verb units) in the sentence. We can separate them to make it easier to figure out the subjects. We can transform the original sentence into: “My friend was very supportive during this time” and “I have known her for fifteen years.” Examining each of the sentences separately makes it easier to figure out.

Who played hockey?

  • Daria and Oswaldo. There is one compound subject in this sentence.

Often, a whole phrase, often a verbal phrase that begins with “to” or an “-ing” word, will function as a subject. A verbal is a verb that is being used as a noun. It is important to be aware of this, as many students struggle to identify the subject of a sentence when it is a phrase. Consider the example below.

Example 9

  • To write an award-winning novel is my ultimate goal.

When applying the time test, we would discover that “is” is the verb. We would then ask ourselves, “what is my ultimate goal?”  The answer is the subject: To write an award-winning novel.

  • Walking briskly is good exercise.

Because “walking” is usually a verb, it may initially be tricky to recognize that the subject can be located by asking ourselves, “what is good exercise?” The answer is once again the subject: walking.

Compound subjects

A sentence may have more than one person, place, or thing as the subject. These subjects are called compound subjects. Compound subjects are useful when you want to discuss several subjects at once. In the following examples, “Desmond and Maria” and “Books, magazines and online articles” are compound subjects.

Example 10

  • Desmond and Maria have been working on that design for almost a year.
  • Books, magazines, and online articles are all good resources.

Prepositional phrases

You will often read a sentence that has more than one noun or pronoun in it. You may encounter a group of words that includes a preposition with a noun or a pronoun. Prepositions connect a noun, pronoun, or verb to another word that describes or modifies that noun, pronoun, or verb. Common prepositions include in, on, under, near, by, with, and about. A group of words that begin with a preposition is called a prepositional phrase. A prepositional phrase begins with a preposition and modifies or describes a word. It cannot act as the subject of a sentence. The following example includes the prepositional phrases “on a business trip,” “with the famous pizza,” “on the way,” and “for lunch.”

  • We went on a business trip.  That restaurant with the famous pizza was on the way. We stopped for lunch.

Exercise 1: Identify the subjects and the prepositional phrases in the following sentences.

  1. The gym is open until nine o’clock tonight.
  2. We went to the store to get some ice.
  3. The student with the most extra credit will win a homework pass.
  4. Maya and Tia found an abandoned cat by the side of the road.
  5. The driver of that pickup truck skidded on the ice.
  6. Anita won the race with time to spare.
  7. The people who work for that company were surprised about the merger.
  8. Working in haste means that you are more likely to make mistakes.
  9. The soundtrack has over sixty songs in languages from around the world.
  10. His latest invention does not work, but it has inspired the rest of us.

Exercise 8.2: On a separate piece of paper, write the following sentences and write “V” above the subject(s) and “S” above the subject(s).

1. The sun never completely disappears during the summer in the Arctic.

2. Following her final exam, Doreen picked up her sister from the airport.

3. She was feeling blue until her favorite song played on her phone.

4. Then she began dancing around the room; her day improved greatly after that.

5. Music can modify our mood greatly, and we can change our mood by listening to different kinds of music with different tempos and in varying keys.


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