3.1 Basic Sentence Structure


This section of Ch. 3 will cover the following topics:

  • subjects, predicates and objects
  • phrases and clauses
  • fragments

Trying to write correctly without understanding is sort of like trying to play baseball if you don’t understand bases, pitches, or hits. You can’t score if you don’t understand how to get to home plate.

Writing is basically a system of structures. Words form , and, eventually, sentences. Ch. 2 focused on words. This chapter looks at how we put words together into sentences.

Sentence Structure

A basic sentence can be broken into two main parts: the subject and the predicate. The subject is who or what performs the action. The predicate is the action. For example:

Samantha sleeps. (“Samantha” is performing the action so she is the subject of the sentence, and “sleeps” is the action she is performing so that is the predicate.)


What’s the difference between a predicate and a verb?

“Verb” names a certain type of word.

“Predicate” is one of the two main parts of a sentence. It usually consists of a verb and its object.

Subjects are always nouns or pronouns. To find the subject of a sentence, find all the nouns and pronouns. Then ask yourself which noun or pronoun is performing the action. For example:

Samantha often sleeps on the sofa. (The nouns in that sentence are “Samantha” and “sofa.” But which noun is performing the action? “Samantha” is sleeping, so “Samantha” is the subject.)

The predicate of a sentence contains the verb. The predicate tells what happened to the subject or what state the subject is in. In the above sentence, “often sleeps on the sofa” is the predicate and “sleeps” is the verb.

The subject is often at the beginning of the sentence, but sometimes it isn’t. For example:

After dinner, Alice served cake. (“Alice” is the subject and “served” is the verb; “After dinner” is a prepositional phrase that tells us when the action happened.)

Sometimes sentences have two subjects. For example:

Alice and Juan walked to school. (“Alice” and “Juan” are the subjects; they both did the action. The word “and” isn’t part of the subject; it is a conjunction that joins the two subjects.)

Sentences can also have more than one verb. For example:

Samantha studies at her desk, sleeps on the couch, and drives to school. (Samantha does three things: “studies,” “sleeps,” and “drives.” All three of those words are verbs.)

Phrases and Clauses

Groups of words are called “phrases” or “clauses.” (In Ch. 2, we studied one type of phrase: a prepositional phrase.)

A phrase is a group of words that does not contain a sentence subject or verb.

For example:

  • in the kitchen
  • the long and winding road

A clause is a group of words that does contain a subject and verb.

For example:

  • Luisa cooked lasagna.
  • the journey includes

There are two types of clauses: dependent and independent.

  • Dependent clauses need further information to make a complete sentence. In the above example, “the journey includes” has a subject and a verb but it does not express a complete thought. It is a dependent clause because it depends on additional information to express a complete thought.
  • Independent clauses do not need additional information to stand on their own. In the above example, “Luisa cooked lasagna” has a subject, a verb, and it expresses a complete thought. It is an independent clause.


To review subjects and predicates, click on the icon below for a cartoon video:

Exercise 1

Copy the following sentences into your notebook. Leave room between them to add information.

  1. Linda and Javier danced under the stars.
  2. I have an opinion about the topic.
  3. The fans walked through the gates.
  4. Jamyra ran around the track.
  5. In April, Toby celebrated his birthday.

First, identify the nouns in these sentences.  Write “n” above them.  Then, identify the pronouns and write “pro” above them.

Remember that a subject is the noun or pronoun doing the action. Which noun or pronoun is the subject in each sentence?  Underline it once.

What is the subject doing? That is the verb. Underline verbs twice.

Hint: Subjects and verbs never appear in prepositional phrases, so another way to do this exercise would be to identify the prepositional phrases first. That makes it easier to find the subject and verb of a sentence.

Obviously, most sentences are not as simple as a noun plus a verb: “Eugenio helped.” But writers build upon this basic structure.

One way sentences grow is by adding an “object.” The object of a sentence is the noun or noun phrase or pronoun affected by the action of the verb. In other words, the subject is the person or thing doing something; the object is having something done to it. For example:

Alice baked a cake. (“Alice” is the subject; she is doing the action of baking. “baked” is the action being done by Alice; it is the verb. “cake” received the action of the verb; it is the object.)

Adding is another way to build more complex sentences. For example:

Samantha is a good student who studies from 6 to 9 p.m. every day and often she will fall asleep on the sofa with a book in her lap.

“from 6 to 9 p.m.,” “on the sofa,” “with a book” and “in her lap” are all prepositional phrases; they add information about where and when.

Experienced writers often write complex sentences, but a sentence is not effective just because it is long. Don’t overload your sentences. For example:

The treasure lay buried under the old oak tree, behind the crumbling fifteenth-century wall, near the schoolyard where children played merrily during their lunch hour, unaware of the riches that remained hidden beneath their feet.

If a sentence is cluttered, divide it:

The treasure lay buried under the old oak tree, behind the crumbling fifteenth-century wall. In the nearby schoolyard, children played merrily during their lunch hour, unaware of the riches that remained hidden beneath their feet.

Avoiding Fragments

One of the benefits to understanding subjects and predicates is the ability to identify and avoid sentence fragments.

A complete sentence has a subject and a verb, and expresses a complete thought.

“Samantha sleeps,” fulfills those requirements. It has a subject “Samantha,” a verb “sleeps,” and it expresses a complete thought. Even though it is short, it is a complete sentence.

A fragment is an incomplete sentence.

A fragment may be missing a subject. For example:

Went to the movies last weekend. (Who went to the movies? The subject is missing.)

Or a fragment may be missing a verb. For example:

The statue damaged during the riots. (“damaged” is not a verb; it’s an adjective that describes the noun “statue.” Without a verb, this is a fragment.)

Or a fragment may have both a subject and a verb, but not express a complete thought. For example:

If she feels like going. (This has a subject “she” and a verb “feels.” But the point is unfinished.)

To fix fragments, you have to add what is missing. For example:

  • “Went to the movies last weekend” + subject = Massimo went to the movies last weekend.
  • “The statue damaged during the riots” + verb = The statue damaged during the riots was a symbol of racism.
  • “If she feels like going” + complete thought = If she feels like going, let her.

Exercise 2

In your notebook, add missing information any fragments below. If the sentence is complete, write “Complete.”

Don’t just guess. Identify the parts of speech in the sentence, look for the subject and verb, then make sure the sentence expresses a complete thought.

  1. The band arrived in a limo with their guitars in the trunk.
  2. Entered the classroom and took off his backpack.
  3. Taking a family cruise to Puerto Vallarta.
  4. A kite in the shape of an eagle.
  5. In the park last night, I saw a bat.
  6. Bentley, the next door neighbor, likes.
  7. Blew down in the high wind, but the maple tree was unharmed.


  • A sentence is a group of words with a subject and a verb, and which expresses a complete thought.
  • Adding prepositional phrases and objects makes a sentence more complex.
  • Understanding how a sentence is constructed will help you avoid errors such as fragments.


Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Write On! by Gay Monteverde is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.