Sentence Structure

Introduction

Clauses, Phrases, and Sentence Elements

A clause has a subject and a predicate containing a finite verb. A dependent clause normally has both but cannot stand alone. A phrase lacks a complete subject-finite-verb pairing. The simple subject is the head of the complete subject; the simple predicate is the main verb together with any auxiliary verbs, as in has been working. Objects name who or what receives an action; words after a linking verb can describe the subject. Optional terminology: transitive means taking a direct object; subject/object complements describe or rename the subject/object. Use these terms only when they help explain a sentence.

Structure depends on clauses, not length: simple = one independent clause; compound = at least two independent clauses; complex = one independent plus at least one dependent clause; compound-complex = at least two independent plus at least one dependent clause. Worked example: When the lecture ended, Mara packed her notes, and Luis asked a question is compound-complex.

Objects: who receives what?

A direct object receives the action of a transitive verb. Ask “verb + what?” or “verb + whom?” In “The surgeon performed the operation,” the surgeon performed what? The operation is the direct object.

An indirect object identifies who or what receives the direct object. In “The nurse gave the patient medication,” the nurse gave what? Medication (direct object) to whom? The patient (indirect object).

Do not confuse an object with the subject or with a possessive word such as his. In an active clause the subject may perform an action; in a passive clause it can receive the action ("The chart was revised"), and with a linking verb it can be described ("The chart is clear").

Why This Matters: Use language structure and context to choose clear, accurate sentences in academic and everyday writing.

What You Need to Know

A complete sentence must have:

1. A subject (who or what)
2. A verb (action or state of being)
3. A complete thought

🧠 Memory Trick

Complete sentence = SVT

• Subject (who/what)
• Verb (did what)
• Complete Thought (makes sense alone)

Fragments = Missing pieces Run-ons = Too many pieces jammed together

Sentence Fragments

A fragment is an incomplete sentence — it's missing a subject, verb, or complete thought.

Types of Fragments:

Fixing Fragments:

Fragment: "Because the patient was stable." Fixed: "Because the patient was stable, she was discharged."

Fragment: "The nurse in the emergency room." Fixed: "The nurse in the emergency room assessed the patient."

Run-On Sentences

A run-on joins two or more complete sentences incorrectly.

Types of Run-Ons:

Fused sentence: No punctuation between clauses

• ✗ "The patient improved she went home."

Comma splice: Only a comma between clauses

• ✗ "The patient improved, she went home."

Four Ways to Fix Run-Ons:

Sentence Types

By Structure:

Purpose and ending punctuation

A statement (declarative) usually ends with a period; a question (interrogative) with a question mark. A command (imperative), such as “Close the door,” has an understood subject you and usually ends with a period. An exclamation expresses strong emotion and may use an exclamation mark. Use these labels to explain punctuation, not as a separate classification drill.

Independent vs. Dependent Clauses

Dependent clause markers: because, although, when, while, if, since, after, before, unless, until

✏️ Worked Examples

Example 1: Identify the Fragment

Which is a fragment?

• A) The nurse documented the findings.
• B) While checking the patient's vitals.

Step 1 — Check option A using the SVT test (Subject + Verb + complete Thought):

• Subject: nurse ✓
• Verb: documented ✓
• Complete thought: "The nurse documented the findings." → Does this make sense on its own? Yes. ✓
• Result: Complete sentence.

Step 2 — Check option B using the SVT test:

• Subject: (none stated) — there's no subject telling us who is checking.
• Verb: checking — this is a present participle, not a finite (main) verb.
• Complete thought: "While checking the patient's vitals." → Does this make sense on its own? No — you're left wondering: who did what while checking? ✗
• Result: Fragment — it's an introductory participial phrase dangling alone.

Step 3 — "While checking the patient's vitals" is an introductory participial phrase, not a full clause: it has no subject and no finite verb ("checking" is a participle). A participial phrase like this must attach to an independent clause to complete the thought. (Contrast a true dependent clause, which does have a subject and finite verb but still can't stand alone, e.g. "While the nurse checked the vitals.")

Answer: B — it's a fragment because "While checking the patient's vitals" is an introductory participial phrase with no subject, no finite verb, and no main clause attached.

How to fix it: "While checking the patient's vitals, the nurse noticed a change." Now it's complete.

Example 2: Fix the Run-On

Run-on: "The medication was administered the patient felt better."

Step 1 — Read the sentence and find where one complete thought ends and another begins:

• "The medication was administered" → Complete sentence (subject: medication, verb: was administered)
• "the patient felt better" → Complete sentence (subject: patient, verb: felt)

Step 2 — Two complete sentences are jammed together with no punctuation between them. That's a fused sentence (the worst type of run-on).

Step 3 — Apply each of the four fixes:

Fix 1 — Period: "The medication was administered. The patient felt better." (Two separate sentences. Simple and clear.)

Fix 2 — Semicolon: "The medication was administered; the patient felt better." (Keeps the connection between the ideas. Both must still be complete sentences.)

Fix 3 — Comma + FANBOYS: "The medication was administered, and the patient felt better." (The "and" shows these things happened together.)

Fix 4 — Subordinating conjunction: "After the medication was administered, the patient felt better." (Now one clause depends on the other, creating a complex sentence.)

All four are correct. Which one is best? It depends on the context and what relationship you want to show between the ideas.

Example 3: Identify Sentence Type

Sentence: "Although the test was negative, the doctor ordered a follow-up."

Step 1 — Find all the clauses (a clause is a group of words with a subject and verb):

• Clause 1: "Although the test was negative" → Subject: test, Verb: was
• Clause 2: "the doctor ordered a follow-up" → Subject: doctor, Verb: ordered

Step 2 — Determine what type each clause is:

• Clause 1 starts with "Although" — that's a subordinating conjunction (dependent clause marker). So this clause cannot stand alone. It's a dependent clause.
• Clause 2 has no subordinating word. "The doctor ordered a follow-up" makes complete sense on its own. It's an independent clause.

Step 3 — Match the combination to a sentence type:

• One independent clause = Simple sentence
• Two independent clauses = Compound sentence
• One independent + one dependent clause = Complex sentence
• Two independent + at least one dependent = Compound-complex sentence

Answer: Complex — one independent clause + one dependent clause.

🏥 TEAS Tip: The test isn't trying to trick you with complex grammar vocabulary — it's checking whether you can tell when something is a complete thought. If a clause starts with "although, because, when, while, if, since," it's dependent and needs a partner.

💡 Pro Tips

• Every sentence needs a subject AND a verb — check for both
• Dependent clauses can't stand alone — they need an independent clause
• Comma + FANBOYS fixes comma splices — but you need BOTH
• "Because" and "Although" start dependent clauses — they need more
• On the TEAS: Know how to identify and fix fragments and run-ons

⚠️ Common Mistakes to Avoid

• Thinking all short sentences are fragments: "Stop." is a complete sentence (imperative)
• Comma splice: Using just a comma to join two sentences
• Starting with "Because" and stopping: "Because she was sick" is incomplete
• Confusing phrases and clauses: A clause has a subject + verb; a phrase doesn't

Quick Reference

Complete Sentence Requirements

✓ Subject (who/what) ✓ Verb (action/being) ✓ Complete thought

Fixing Run-Ons

Dependent Clause Starters

because, although, when, while, if, since, after, before, unless, until

Sentence structure mastered! 💪 Next up: Commonly Confused Words