Writing Complete Sentences
Definition
A complete sentence is a group of words that expresses a complete thought. Every complete sentence must contain at least two essential parts: a subject (who or what the sentence is about) and a predicate (what the subject does, is, or experiences). A sentence must also be able to stand alone and make sense by itself.
Incomplete sentences — also called fragments — are one of the most common writing errors. A fragment is missing the subject, the verb, or both, and it leaves the reader confused because the thought is unfinished.
The Three Rules of Complete Sentences
Rule 1: Every sentence must have a subject.
The subject tells us who or what the sentence is about. It is usually a noun or pronoun. Without a subject, the sentence is incomplete.
Examples
1. Maria writes in her journal every morning. (Subject: Maria)
2. The old library on Fifth Avenue burned down last Tuesday. (Subject: The old library on Fifth Avenue)
3. They decided to move to a smaller apartment. (Subject: They)
4. Coffee and tea are popular beverages in the United States. (Subject: Coffee and tea)
5. Running ten miles every weekend builds incredible endurance. (Subject: Running ten miles every weekend)
Rule 2: Every sentence must have a verb.
The verb tells us what the subject does, what state it is in, or what happens to it. Without a verb, a sentence is always a fragment.
Examples
1. The professor explained the assignment in great detail.
2. Children in the neighborhood play basketball until dark.
3. The economy has improved significantly over the past three years.
4. She was exhausted after the long flight from Seoul.
5. Our team will present the final report on Friday afternoon.
Rule 3: Every sentence must express a complete thought.
Even if a group of words has a subject and a verb, it may still be a fragment if it does not express a complete thought. Subordinating conjunctions such as ‘because,’ ‘although,’ ‘when,’ and ‘if’ introduce dependent clauses that cannot stand alone.
Examples of INCORRECT fragments vs. CORRECT sentences
1. WRONG: Because she studied for weeks. / CORRECT: Because she studied for weeks, she passed the exam with confidence.
2. WRONG: Although the rain was heavy. / CORRECT: Although the rain was heavy, the game continued without delay.
3. WRONG: When the director finally arrived. / CORRECT: When the director finally arrived, the meeting immediately began.
4. WRONG: If you want to succeed in business. / CORRECT: If you want to succeed in business, you must communicate your ideas effectively.
5. WRONG: Which was the most surprising result of the study. / CORRECT: This was the most surprising result of the study.
Extended Dialogue: Complete Sentences in Action
Setting: A university writing center. A student named Carlos meets with a writing tutor named Ms. Brooks to review his first draft essay.
Ms. Brooks: Carlos, I’ve read through your introduction, and overall your ideas are really interesting. But I noticed a few places where you have what we call sentence fragments. Do you know what those are?
Carlos: I think so. Is a fragment like a sentence that isn’t finished?
Ms. Brooks: Exactly right! A fragment is missing something — usually the subject, the verb, or the complete thought. For example, you wrote here: ‘Because many students struggle with time management.’ Can you tell me what’s wrong with that?
Carlos: Hmm. It starts with ‘because,’ so… is it waiting for more information?
Ms. Brooks: Perfect! That ‘because’ makes it a dependent clause — it depends on another clause to be complete. The reader is left wondering: ‘They struggle with time management — so what happens?’
Carlos: Oh! So I need to add the result? Like, ‘Because many students struggle with time management, they often fall behind in their coursework’?
Ms. Brooks: That is a wonderful correction! Now it is a complete sentence. It has a subject — ‘they’ — a verb — ‘fall behind’ — and it expresses a complete thought. You also have another issue on page two: ‘Which caused a major change in university policy.’ That’s a relative clause fragment.
Carlos: So I need to attach it to a sentence before it?
Ms. Brooks: One option is to attach it. For instance: ‘The new research results caused a major change in university policy.’ Now ‘The new research results’ is your subject, and ’caused’ is your verb.
Carlos: I see. I think I was writing fast and not checking whether each sentence could stand alone.
Ms. Brooks: That is a very common issue! Here is a trick: after writing each sentence, ask yourself three questions. First — who or what is doing something? That is your subject. Second — what are they doing or what is happening? That is your verb. Third — does this thought make complete sense by itself? If you can answer yes to all three, you have a complete sentence.
Carlos: That is a great method. I will go through my essay again tonight and check every sentence with those three questions.
Ms. Brooks: Excellent plan. Strong sentences are the foundation of strong writing. Once you master this, everything else becomes much easier.
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