Key Takeaways

  • Complete sentences have a subject, predicate, and express a complete thought
  • Fragments are incomplete; run-ons are improperly joined sentences
  • Use coordinating conjunctions (FANBOYS) or semicolons to join independent clauses
  • Items in a series must have parallel structure
  • Place modifiers close to the words they describe
Last updated: January 2026

Sentence Structure

Understanding sentence structure helps you identify errors and write clear, effective sentences. The ParaPro tests your ability to recognize complete sentences and common structural problems.

Parts of a Sentence

Subject: Who or what the sentence is about Predicate: What the subject does or is (includes the verb)

Example: The excited students | cheered loudly.

  • Subject: The excited students
  • Predicate: cheered loudly

Sentence Types by Structure

TypeDefinitionExample
SimpleOne independent clauseThe teacher explained the lesson.
CompoundTwo independent clauses joinedThe teacher explained, and the students listened.
ComplexIndependent + dependent clauseWhen the bell rang, students left.
Compound-ComplexTwo independent + one dependentWhen the bell rang, students left, and they went home.

Independent vs. Dependent Clauses

Clause TypeDefinitionExample
IndependentComplete thought; can stand aloneStudents left the classroom.
DependentIncomplete thought; needs moreWhen the bell rang...

Subordinating Conjunctions (start dependent clauses):

  • Time: when, while, after, before, until
  • Cause: because, since
  • Condition: if, unless
  • Contrast: although, even though

Sentence Errors

Sentence Fragments

Fragment: An incomplete sentence (missing subject, verb, or complete thought)

  • ✗ Running down the hall.

  • ✓ The student was running down the hall.

  • ✗ Because it was raining.

  • ✓ We stayed inside because it was raining.

Run-On Sentences

Run-on: Two sentences incorrectly joined

  • ✗ I went to school I saw my friends.

Fixes:

  • Period: I went to school. I saw my friends.
  • Comma + conjunction: I went to school, and I saw my friends.
  • Semicolon: I went to school; I saw my friends.

Comma Splices

Comma splice: Two sentences joined only by a comma

  • ✗ I went to school, I saw my friends.

Fixes: Same as run-ons

Parallel Structure

Items in a list or series should have the same grammatical form.

Not Parallel:

  • ✗ She likes reading, to swim, and basketball.

Parallel:

  • ✓ She likes reading, swimming, and playing basketball.
  • ✓ She likes to read, to swim, and to play basketball.

Modifier Placement

Misplaced modifiers are in the wrong position:

  • ✗ I saw a dog walking to school. (Was the dog walking to school?)
  • ✓ Walking to school, I saw a dog.

Dangling modifiers have no clear word to modify:

  • ✗ After eating lunch, the bell rang. (The bell ate lunch?)
  • ✓ After eating lunch, the students heard the bell ring.

Classroom Application

Help students with sentence structure by:

  • Using sentence frames for practice
  • Identifying subject and predicate in color
  • Teaching fragment vs. sentence identification
  • Practicing combining simple sentences
  • Reading sentences aloud to check for completeness
Test Your Knowledge

Which sentence is a fragment?

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B
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D
Test Your Knowledge

Which sentence shows parallel structure?

A
B
C
D