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Grammar for TOEFL Writing: Run-ons and Fragments



Why Sentence Structure Matters in TOEFL Writing

In TOEFL writing, long or complex sentences can help improve scores, but only if ideas are connected properly. Incorrectly formed sentences may turn into fragments or run-ons, which hurts both clarity and your score.

Building Correct Sentences

Essential Parts of a Sentence

Every sentence requires a subject (who or what the sentence is about) and a verb (the action or state). Sometimes, a verb also needs an object or complement to complete its meaning.

  • Example:

    • "I studied for the exam." (complete)

    • "I studied math." (verb + object)

Four Sentence Types

  • Simple: One independent clause.

  • Compound: Two or more independent clauses joined with a coordinating conjunction (and, but, or, so, yet, nor, for).

  • Complex: One independent clause plus one or more dependent clauses, using subordinators such as because, although, if, when.

  • Compound-complex: At least two independent clauses plus at least one dependent clause.

Fixing Run-On Sentences

  • Split into separate sentences:

    • "Running is like a drug. Long-distance runners are in euphoria."

  • Use a conjunction:

    • "Running is like a drug, and long-distance runners are in euphoria."

    • "Running is like a drug, since long-distance runners are in euphoria."

  • Use a semicolon or colon:

    • "Running is like a drug; long-distance runners are in euphoria."

    • "Running is like a drug: long-distance runners are in euphoria."

Fixing Sentence Fragments

Fragments with No Subject

  • Example (incorrect): "For most people who have dogs live longer, happier lives."

  • Correction: "Most people who have dogs live longer, happier lives."

Fragments with No Verb

  • Example (incorrect): "My favorite teacher, an expert in history and literature."

  • Correction: "My favorite teacher is an expert in history and literature."

Fragments with No Independent Clause

  • Example (incorrect): "Due to the unforeseen circumstances, including the sudden power outage, the unexpected equipment failure, and the last-minute cancellation of the keynote speaker."

  • Correction: "Due to the unforeseen circumstances, including the sudden power outage, the unexpected equipment failure, and the last-minute cancellation of the keynote speaker, the event was postponed."