Faulty Sentence Structure
Sentence Fragments
A sentence fragment is an incomplete sentence that lacks a subject, a verb, or a complete thought. Every grammatical sentence needs at least one independent clause — a group of words with a subject and a verb that can stand alone. A fragment fails this test because it is missing one of these essential elements or because it begins with a subordinating conjunction and is never attached to an independent clause.
Missing subject: "Walked to the store." — who walked? No subject.
Missing verb: "The tall man in the corner." — no action or state verb.
Subordinate clause standing alone: "Because she was tired." — a dependent clause that needs an independent clause to complete it.
Phrase treated as a sentence: "Running through the park at sunset." — a participial phrase with no main clause.
There are three standard ways to fix a sentence fragment: attach it to an adjacent independent clause, add the missing subject or verb, or remove the subordinating conjunction that makes the clause dependent.
Attach to a main clause: "Because she was tired. She went to bed early." → "Because she was tired, she went to bed early."
Add the missing element: "Walked to the store." → "He walked to the store."
Remove the subordinator: "Because she was tired." → "She was tired."
Run-On Sentences
A run-on sentence occurs when two or more independent clauses are joined without proper punctuation or an appropriate coordinating conjunction. There are two main types: a fused sentence, where independent clauses are pushed together with no punctuation at all, and a comma splice, where independent clauses are joined only by a comma. Both are errors because a comma alone cannot separate independent clauses.
Fused sentence: "I love physics it is my favourite subject." — no punctuation or connector between the two independent clauses.
Comma splice: "I love physics, it is my favourite subject." — only a comma separates the two independent clauses, which is insufficient.
Why it matters: Without correct boundaries, the reader cannot tell where one idea ends and the next begins, creating ambiguity.
Run-on sentences can be corrected in five ways: use a period, use a semicolon, use a comma plus a coordinating conjunction, use a subordinating conjunction to make one clause dependent, or restructure the sentence entirely.
Period: "I love physics. It is my favourite subject."
Semicolon: "I love physics; it is my favourite subject."
Comma + coordinating conjunction: "I love physics, and it is my favourite subject."
Subordinating conjunction: "I love physics because it is my favourite subject."
Restructure: "Physics is my favourite subject, which I love."
Misplaced Modifiers
A misplaced modifier is a word, phrase, or clause that is placed too far from the noun or pronoun it is meant to modify, causing confusion or unintentional humour. In English, modifiers should generally appear directly next to the word they describe. When a modifier drifts away from its target, the sentence can become ambiguous or absurd.
Position matters: "The student almost solved every problem on the test." means the student came close to solving every problem but may not have solved any. "The student solved almost every problem on the test." means the student solved most of the problems.
Prepositional phrase ambiguity: "I saw the man with the telescope." — who has the telescope? The speaker or the man?
Adverb placement: "She only told her friend." vs. "She told only her friend." — the position of "only" changes the meaning entirely.
Dangling Modifiers
A dangling modifier is a modifier (usually a participial or infinitive phrase) at the beginning of a sentence that has no logical subject in the sentence to attach to. Unlike a misplaced modifier, which is simply too far from its target, a dangling modifier has no appropriate target at all — the noun it should describe is entirely absent from the sentence.
Participial phrase with no subject: "Walking through the park, the flowers smelled wonderful." — the sentence implies the flowers were walking.
Infinitive phrase with no subject: "To win the tournament, practice is necessary." — practice cannot win the tournament; a player can.
Key test: Read the introductory modifier and then check the subject of the main clause. If the subject does not logically perform the action in the modifier, the modifier is dangling.
Parallel Structure (Parallelism)
Parallel structure (also called parallelism) means using the same grammatical form for elements that have the same function in a sentence. When items are in a list, a comparison, or a paired construction (such as both...and, either...or, not only...but also), each element must follow the same pattern — all nouns, all gerunds, all infinitives, or all clauses. Breaking this pattern creates a parallelism error.
Lists: "She likes hiking, swimming, and to ride bikes." → faulty. Correct: "She likes hiking, swimming, and riding bikes." (all gerunds).
Paired conjunctions: "He is both intelligent and works hard." → faulty. Correct: "He is both intelligent and hardworking." (both adjectives).
Comparisons: "The new model is faster than the old one and has more memory." → correct parallelism: two verb phrases. "The new model is faster and has more memory than the old one." → also correct.
Headings and outlines: Each item at the same level of an outline should use the same grammatical form.
Common Parallelism Markers
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and → joins two items of the same form
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or / nor → alternatives of the same form
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both ... and → paired items of the same form
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either ... or → paired alternatives of the same form
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neither ... nor → paired negatives of the same form
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not only ... but also → paired emphasis of the same form
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whether ... or → paired alternatives of the same form
Parallelism applies beyond simple lists — it governs comparisons, headings, and any series of grammatically equivalent elements. Recognising the pattern a sentence establishes and then checking that every element follows it is the core skill.
Verb phrases in series: "She wants to study engineering, to design bridges, and building cities." → correct parallel: "to study engineering, to design bridges, and to build cities."
Noun phrases: "The course covers cell biology, genetics, and how organisms evolve." → correct parallel: "cell biology, genetics, and evolution."
Adjective series: "The solution was quick, efficient, and it was accurate." → correct parallel: "quick, efficient, and accurate."
Diagnostic Checklist for Faulty Sentence Structure
When editing any sentence for structural correctness, work through this checklist in order. Each check targets one of the six fault types covered above.
Step 1 — Find the main clause: Identify the subject and verb. If neither exists, the sentence is a sentence fragment.
Step 2 — Count independent clauses: If two or more independent clauses appear, check the punctuation and connector between them. A missing separator means a run-on sentence; a lone comma means a comma splice.
Step 3 — Locate modifiers: For each modifier, find the noun it describes. If the nearest noun is the wrong one, the modifier is misplaced. If no logical noun exists, it is dangling.
Step 4 — Check parallel forms: In every list, comparison, or paired construction, confirm that all elements share the same grammatical form. If not, there is a parallelism error.