How to Write a Complete Sentence: Parts & Structure

Instructor: Bethany Calderwood

Bethany has taught special education in grades PK-5 and has a master's degree in special education.

The most basic building block of writing is the sentence. This lesson describes the parts of a sentence, how to write a complete sentence, and two sentence errors to avoid.

Look Your Best

Whether through blogs, on-line forums, or social media, we all communicate with strangers and friends in print. In a digital world full of internet slang and emoticons, it is tempting to take shortcuts in writing, assuming our readers will figure out our meaning. But in professional and academic writing, and even in personal writing, the ability to write in complete sentences is a powerful tool. Complete sentences make us look and sound good, and make it most likely that we actually say what we mean. Let's explore the components of a complete sentence: the subject, predicate, punctuation, and capitalization.

The Subject of the Sentence

Simple Subject

The simple subject of the sentence is a noun (person, place, thing, or idea) or pronoun (word that replaces a noun: he, she, we, they, etc) that tells who or what the sentence is about.

  • Jennifer cried.

The simple subject is ''Jennifer.''

  • The phone rang.

The simple subject is ''phone.''

Complete Subject

The complete subject of a sentence contains the simple subject, as well as any modifying words or phrases that go with it.

  • The loudly ticking clock hung on the wall.

The complete subject is ''The loudly ticking clock.'' The simple subject is ''clock,'' which is described by ''The loudly ticking.''

The Predicate of the Sentence

Simple Predicate

The simple predicate of the sentence is a verb (word that shows action or being) that tells what the subject does or is.

  • Marco sang.

The simple predicate is ''sang.''

  • The new neighbor is friendly.

The simple predicate is ''is.''

Complete Predicate

The complete predicate of the sentence contains the verb and any modifiers. If the verb is an action verb, the predicate could also contain direct and indirect objects - words that receive the action of the verb. If the verb is a linking verb, the predicate contains the subject complements - adjectives or nouns that identify or rename the subject.

  • Benjamin ate three cookies.

The simple predicate is ''ate.'' The complete predicate is ''ate three cookies.'' ''Cookies'' is the direct object, telling what was eaten, and ''three'' describes how many cookies.

  • Susanna is Benjamin's mom.

The simple predicate is ''is.'' The complete predicate is ''is Benjamin's mom.'' The word ''mom'' is a subject complement. The word ''Benjamin's'' describes mom.

Capitalization and Punctuation

A complete sentence begins with a capital letter and ends with a punctuation mark. These are the sentence parts that we tend to skip, especially when texting, emailing, and commenting on social media. But in writing, these two conventions help to shape the text. They tell us where one thought ends and another begins, and they make writing more visually appealing. Punctuation marks also add information about the tone and inflection of a sentence.


The first letter of the first word of a sentence must be capitalized. After that, the only words that should be capitalized are proper nouns such as the names of people and places.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account