Key Takeaways

  • Sentences need both a subject and a complete predicate to avoid being fragments
  • Run-ons can be fixed with proper punctuation, conjunctions, or subordination
  • A comma alone cannot join two independent clauses (comma splice)
  • Parallel structure requires matching grammatical forms in lists and comparisons
  • Modifiers must be placed near the words they modify to avoid confusion
Last updated: January 2026

Sentence Structure

Understanding sentence structure helps you construct clear, grammatically correct sentences. The TEAS tests your ability to identify sentence types, avoid fragments and run-ons, and use clauses correctly.

Sentence Components

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

Example: The nurse (subject) administered the medication (predicate).

Phrases vs. Clauses

TypeDefinitionExample
PhraseGroup of words WITHOUT a subject-verb pair"in the morning," "running quickly"
ClauseGroup of words WITH a subject-verb pair"when she arrived," "the patient slept"

Types of Clauses:

TypeDefinitionCan Stand Alone?
IndependentExpresses complete thoughtYes
DependentCannot stand alone (starts with subordinator)No

Sentence Types by Structure

TypeStructureExample
SimpleOne independent clauseThe nurse checked vitals.
CompoundTwo+ independent clausesThe nurse checked vitals, and the doctor reviewed the chart.
ComplexIndependent + dependent clauseWhen the patient arrived, the nurse checked vitals.
Compound-ComplexTwo+ independent + dependentWhen the patient arrived, the nurse checked vitals, and the doctor was notified.

Joining Independent Clauses

Correct methods:

MethodPunctuationExample
Comma + coordinating conjunction, and/but/orShe ran tests, and she called the doctor.
Semicolon;She ran tests; she called the doctor.
Semicolon + conjunctive adverb; however,She ran tests; however, results were normal.
Period.She ran tests. She called the doctor.

Sentence Fragments

A fragment is an incomplete sentence missing a subject, verb, or complete thought.

Examples of Fragments:

  • ❌ "Running down the hall." (no subject)
  • ❌ "The patient who came in yesterday." (no complete predicate)
  • ❌ "Because she was tired." (dependent clause alone)

Corrections:

  • ✅ "The nurse was running down the hall."
  • ✅ "The patient who came in yesterday was discharged."
  • ✅ "She went home because she was tired."

Run-On Sentences

A run-on joins independent clauses incorrectly.

Types of Run-Ons:

TypeErrorExample
Fused sentenceNo punctuation between clausesThe patient arrived the nurse took vitals.
Comma spliceOnly a comma between clausesThe patient arrived, the nurse took vitals.

Corrections:

  • ✅ Add period: "The patient arrived. The nurse took vitals."
  • ✅ Add comma + conjunction: "The patient arrived, and the nurse took vitals."
  • ✅ Add semicolon: "The patient arrived; the nurse took vitals."
  • ✅ Add subordination: "When the patient arrived, the nurse took vitals."

Parallel Structure

Parallelism means using the same grammatical form for items in a list or comparison.

Incorrect: "The nurse enjoys helping patients, teaching students, and to do research." Correct: "The nurse enjoys helping patients, teaching students, and doing research."

Incorrect: "The procedure is both effective and has minimal risks." Correct: "The procedure is both effective and safe."

Modifier Placement

Misplaced Modifier: Modifier placed far from what it describes.

  • ❌ "The doctor gave instructions to the patient wearing a white coat."
  • ✅ "The doctor wearing a white coat gave instructions to the patient."

Dangling Modifier: Modifier with no clear word to modify.

  • ❌ "After reviewing the chart, the medication was administered."
  • ✅ "After reviewing the chart, the nurse administered the medication."

Subject-Verb Agreement

Rules:

  • Singular subjects take singular verbs
  • Plural subjects take plural verbs
  • Words between subject and verb don't change agreement

Examples:

  • "The nurse is here." (singular)
  • "The nurses are here." (plural)
  • "The group of nurses is here." (singular—"group" is subject)
  • "Each of the patients needs attention." (singular—"each" is subject)
Test Your Knowledge

Which of the following is a comma splice?

A
B
C
D
Test Your Knowledge

Which sentence demonstrates correct parallel structure?

A
B
C
D
Test Your Knowledge

Which sentence contains a dangling modifier?

A
B
C
D