The Sentence
Lesson 7: Sentence Fragments
Lesson: 7 of 9 | Level: 🟢 Elementary
1. Lesson Overview
A sentence fragment is one of the most common errors in written English. It occurs when a group of words is punctuated as a sentence — beginning with a capital letter and ending with a full stop — but fails to meet the grammatical requirements of a complete sentence. It is, in other words, a sentence that is not quite a sentence.
Fragments appear in the writing of learners at every level, and they appear for a variety of reasons. Some lack a subject. Some lack a finite verb. Some contain both but are dependent clauses that have been separated from the main clause they belong to. Each type requires a different correction.
Understanding sentence fragments — what they are, why they occur, and how to fix them — is one of the most practical skills this course can offer. This lesson addresses all three.
Objectives
By the end of this lesson, you will be able to:
- Define a sentence fragment and explain why it is a grammatical error
- Identify the main types of sentence fragments
- Correct sentence fragments using appropriate strategies
- Recognise and avoid sentence fragments in your own writing
2. Core Content
A. Defining a Sentence Fragment
A sentence fragment is a group of words that is punctuated as a complete sentence but lacks one or more of the three requirements of a grammatically complete sentence — a subject, a finite verb, and a complete thought.
Consider the following:
The ancient rainforest near the coast. Because the temperature dropped below freezing. Running along the fault line for hundreds of kilometres.
None of these is a complete sentence. The first has no finite verb. The second has a subject and a finite verb but is a dependent clause — it does not express a complete thought. The third has no subject and no finite verb — only a participial phrase.
All three are sentence fragments. All three would be errors in formal written English.
B. Types of Sentence Fragments
Type 1 — The Missing-Verb Fragment
A missing-verb fragment is a noun phrase — or a noun phrase with modifying words — that has no finite verb. It names something but says nothing about it.
For example:
The deepest point on Earth, located in the Mariana Trench in the western Pacific Ocean. A remarkable diversity of plant and animal species found nowhere else in the world.
In the first example, located in the Mariana Trench in the western Pacific Ocean is a participial phrase modifying the noun phrase — but there is no finite verb to complete the sentence. In the second, found nowhere else in the world is again a participial phrase — not a finite verb.
How to correct it: Add a finite verb to complete the sentence.
| Fragment | Correction |
|---|---|
| The deepest point on Earth, located in the Mariana Trench. | The deepest point on Earth is located in the Mariana Trench. |
| A remarkable diversity of species found nowhere else in the world. | A remarkable diversity of species is found nowhere else in the world. |
Type 2 — The Missing-Subject Fragment
A missing-subject fragment contains a finite verb and often additional words, but has no subject performing the action.
For example:
Studied the migration patterns of humpback whales for over two decades. Has transformed our understanding of the deep ocean in remarkable ways.
In the first example, studied is a finite verb — but who studied? There is no subject. In the second, has transformed is a finite verb — but what has transformed? Again, no subject is present.
How to correct it: Add a subject to the fragment.
| Fragment | Correction |
|---|---|
| Studied the migration patterns of humpback whales for over two decades. | The research team studied the migration patterns of humpback whales for over two decades. |
| Has transformed our understanding of the deep ocean in remarkable ways. | The development of deep-sea submersibles has transformed our understanding of the deep ocean in remarkable ways. |
Type 3 — The Dependent-Clause Fragment
A dependent-clause fragment contains both a subject and a finite verb but has been separated from the main clause it belongs to. It is introduced by a subordinating conjunction — such as although, because, when, since, if, or unless — or a relative pronoun — such as who, which, or that.
For example:
Although the Amazon basin receives heavy rainfall throughout the year. Which has retreated by more than 50 per cent since measurements began in 1900. Because rising ocean temperatures are causing widespread coral bleaching.
Each of these contains a subject and a finite verb, but none expresses a complete thought. The reader is left waiting for the main clause that never arrives.
How to correct it: Attach the dependent clause to a main clause, or remove the subordinating conjunction to make it an independent clause.
| Fragment | Correction — Attach to Main Clause | Correction — Remove Conjunction |
|---|---|---|
| Although the Amazon receives heavy rainfall throughout the year. | Although the Amazon receives heavy rainfall throughout the year, some areas experience distinct dry seasons. | The Amazon receives heavy rainfall throughout the year. |
| Because rising temperatures are causing widespread coral bleaching. | Because rising temperatures are causing widespread coral bleaching, many reef ecosystems are under severe threat. | Rising temperatures are causing widespread coral bleaching. |
Type 4 — The Participial-Phrase Fragment
A participial-phrase fragment begins with a present participle (-ing form) or a past participle and functions as a modifier — but it has no subject and no finite verb of its own.
For example:
Flowing eastward through nine countries before emptying into the Atlantic Ocean. Discovered in the hydrothermal vent ecosystems of the deep Pacific in 1977. Running along the fault line for hundreds of kilometres through some of the most seismically active terrain on Earth.
None of these has a subject performing an action or a finite verb expressing that action. Each is a participial phrase punctuated as if it were a complete sentence.
How to correct it: Attach the participial phrase to a main clause whose subject it clearly modifies.
| Fragment | Correction |
|---|---|
| Flowing eastward through nine countries before emptying into the Atlantic Ocean. | The Amazon flows eastward through nine countries before emptying into the Atlantic Ocean. |
| Discovered in the hydrothermal vent ecosystems of the deep Pacific in 1977. | Hydrothermal vent ecosystems, discovered in the deep Pacific in 1977, support life without sunlight. |
Type 5 — The Infinitive-Phrase Fragment
An infinitive-phrase fragment begins with a to-infinitive and functions as a noun, adjective, or adverb — but it has no subject and no finite verb.
For example:
To understand the long-term effects of deforestation on global climate patterns. To map the entire ocean floor using the latest generation of autonomous underwater vehicles.
Both begin with to + verb and contain a great deal of information — but neither has a subject performing a finite verb. Neither is a complete sentence.
How to correct it: Attach the infinitive phrase to a main clause or rewrite it with a finite verb.
| Fragment | Correction |
|---|---|
| To understand the long-term effects of deforestation on global climate patterns. | Scientists are working to understand the long-term effects of deforestation on global climate patterns. |
| To map the entire ocean floor using autonomous underwater vehicles. | The goal of the project is to map the entire ocean floor using autonomous underwater vehicles. |
C. Intentional Fragments
It is worth noting that sentence fragments are not always errors. In literature, journalism, advertising, and spoken English, fragments are sometimes used deliberately for stylistic effect — to create emphasis, rhythm, or dramatic impact.
For example:
What caused the mass extinction of the dinosaurs? A meteorite. Or perhaps volcanic activity. Or both. The results were in. Conclusive. Undeniable. Historic.
In both passages, the fragments — a meteorite, conclusive, undeniable, historic — are clearly intentional. They create a staccato rhythm that adds emphasis and drama. This is an accepted stylistic device in creative and journalistic writing.
However, in formal, academic, and professional writing, sentence fragments are not acceptable — intentional or otherwise. In this course, the standard is that of formal written English, and every sentence should be grammatically complete.
3. Usage in Context
| Rule | Example |
|---|---|
| Every sentence in formal writing must contain a subject and a finite verb and express a complete thought. | The glacier has retreated by more than 40 per cent since 1900. |
| A noun phrase without a finite verb is a fragment — add a verb to complete it. | ❌ The ancient volcanic crater near the coast. ✅ The ancient volcanic crater near the coast is still visible from the air. |
| A participial phrase without a main clause is a fragment — attach it to a main clause. | ❌ Discovered in 1977. ✅ Hydrothermal vents, discovered in 1977, transformed our understanding of life on Earth. |
| A dependent clause introduced by a subordinating conjunction cannot stand alone. | ❌ Because the permafrost is thawing. ✅ Because the permafrost is thawing, methane is being released into the atmosphere. |
| A relative clause introduced by which, who, or that cannot stand alone. | ❌ Which has retreated significantly since 1900. ✅ The glacier, which has retreated significantly since 1900, is now half its original size. |
| An infinitive phrase cannot stand alone as a sentence. | ❌ To understand the effects of ocean acidification. ✅ Scientists study coral reefs to understand the effects of ocean acidification. |
| Check for fragments by asking: does this group of words have a subject? A finite verb? A complete thought? | Apply all three tests before accepting a group of words as a complete sentence. |
| In formal writing, rewrite all sentence fragments — even those that seem deliberately emphatic. | ❌ A remarkable discovery. ✅ It was a remarkable discovery. |
| A compound predicate must share its subject — do not separate it into a fragment. | ❌ Darwin sailed to the Galápagos. And observed the finches carefully. ✅ Darwin sailed to the Galápagos and observed the finches carefully. |
| Fragments often appear after a complete sentence — check the sentence that follows any full stop carefully. | ❌ The results were published last month. After years of painstaking research. ✅ The results were published last month after years of painstaking research. |
| A present participle (-ing form) without an auxiliary verb cannot be the main verb of a sentence. | ❌ The glacier retreating every summer. ✅ The glacier retreats every summer. |
| That, which, who, although, because, and since are signals that a dependent clause is coming — ensure it is attached to a main clause. | Although the conditions were extreme, the expedition was completed successfully. |
4. Common Errors and Corrections
| Error ❌ | Correction ✅ | Explanation |
|---|---|---|
| The ancient forest near the river. Rich in biodiversity and largely unexplored. | The ancient forest near the river is rich in biodiversity and largely unexplored. | Two noun phrases without finite verbs — combine them into one complete sentence with a verb. |
| Because global temperatures are rising. Glaciers are retreating worldwide. | Because global temperatures are rising, glaciers are retreating worldwide. | The dependent clause must be attached to the main clause — a full stop between them creates a fragment. |
| Scientists have studied the Amazon for decades. Discovering thousands of new species. | Scientists have studied the Amazon for decades, discovering thousands of new species. | The participial phrase must be attached to the main clause with a comma — not separated by a full stop. |
| To understand the effects of deforestation. Scientists study satellite imagery. | To understand the effects of deforestation, scientists study satellite imagery. | The infinitive phrase of purpose must be attached to the main clause it introduces. |
| The glacier that has retreated most rapidly since 1900. | The glacier that has retreated most rapidly since 1900 is located in Greenland. | A noun phrase followed by a relative clause still requires a finite verb and predicate. |
| Which makes the discovery all the more remarkable. | This makes the discovery all the more remarkable. | A relative clause cannot stand alone — rewrite as an independent clause. |
| Running along the fault line for hundreds of kilometres through seismically active terrain. | The crack runs along the fault line for hundreds of kilometres through seismically active terrain. | A participial phrase has no subject or finite verb — rewrite with both. |
| Although scientists have studied the deep ocean for decades. Many species remain undiscovered. | Although scientists have studied the deep ocean for decades, many species remain undiscovered. | The dependent clause and main clause belong together — replace the full stop with a comma. |
| A new species of deep-sea jellyfish. Found near the Mariana Trench by a research team in 2023. | A new species of deep-sea jellyfish was found near the Mariana Trench by a research team in 2023. | Two fragments — combine them by adding the finite verb was found. |
| Darwin observed the finches. And noticed significant differences between the birds on different islands. | Darwin observed the finches and noticed significant differences between the birds on different islands. | A compound predicate must not be separated from its subject by a full stop. |
5. Lesson Mastery
After completing this lesson, you should now be able to:
✅ Define a sentence fragment and explain why it is a grammatical error
✅ Identify the main types of sentence fragments
✅ Correct sentence fragments using appropriate strategies
✅ Recognise and avoid sentence fragments in your own writing