How to build and fix a complete sentence
TEAS 7 outline: Correct sentence structure
Also covers HESI A2 Grammar (Grammar terms)
- Every sentence needs at least one independent clause.
- A dependent clause starts with a word like because or when.
- A dependent clause standing alone is a fragment.
- Join two independent clauses with a period, semicolon, or comma plus FANBOYS.
- A comma alone between two full clauses is a comma splice.
Key facts
- An independent clause has a subject and a verb and expresses a complete thought; it can stand alone as a sentence.
- A dependent clause has a subject and a verb but begins with a marker word such as because, although, when, if, since, while, before or until, so it cannot stand alone.
- Simple = one independent clause; compound = two or more independent clauses; complex = one independent clause plus at least one dependent clause; compound-complex = two or more independent clauses plus at least one dependent clause.
Show all 6 key factsShow fewer
- A fragment is missing a subject, a verb, or a complete thought; fix it by attaching it to a nearby sentence, adding what is missing, or removing the dependent marker word.
- A run-on (fused sentence) has two independent clauses with nothing between them; a comma splice joins them with only a comma.
- Fix a run-on or comma splice with a period, a semicolon, a comma plus for, and, nor, but, or, yet or so, a semicolon plus a transition like however followed by a comma, or by making one clause dependent.
Quick check1 question · 2 more at the end
Which type of sentence is the following? "The pharmacist counted the tablets, and the technician printed the label."
Correct answer: C.
Count the clauses. "The pharmacist counted the tablets" and "the technician printed the label" each have their own subject and verb and can stand alone, and there is no dependent clause. Two independent clauses joined by a comma and and make a compound sentence.
A A simple sentence has only one independent clause; this one has two, each with its own subject.
B A complex sentence needs a dependent clause, but neither clause starts with a dependent marker such as because or when.
C Correct: two independent clauses are joined by a comma and the conjunction and, with no dependent clause.
D A compound-complex sentence also needs at least one dependent clause, and this sentence has none.
Full lesson
Each part starts with its main idea. Open a part when you want the details.
The short answer: Every sentence needs at least one independent clause, a subject and verb that can stand alone. A dependent clause starts with a word like because or when and cannot stand alone; on its own it is a fragment. Two independent clauses need a period, a semicolon, or a comma plus a conjunction like and, so or but between them.
1 How do you check whether a sentence is built correctly?Count the independent clauses, because that number decides almost every sentence-structure answer. 1 min
Count the independent clauses, because that number decides almost every sentence-structure answer. A sentence can sound smooth and still be broken, so use this method instead of your ear:
- Find every subject–verb pair. Each pair is a clause.
- Check the front of each clause. If it starts with a dependent marker (because, although, when, if, since, while, before, after, until, unless), it is a dependent clause and cannot stand alone.
- Count the independent clauses. Zero means a fragment. Two or more means you must check the joint between them.
- Check each joint. A period, a semicolon, or a comma plus a FANBOYS word (for, and, nor, but, or, yet, so) is correct. A comma alone or nothing at all is an error.
2 What are the four sentence types?Each type is just a count of independent and dependent clauses. 1 min
Each type is just a count of independent and dependent clauses.
| Type | Formula | Example |
|---|---|---|
| Simple | 1 independent | The charge nurse and two aides checked every room before noon. |
| Compound | 2+ independent | The lab results came back early, so the doctor called the patient. |
| Complex | 1 independent + 1+ dependent | The doctor reviewed the scan before she met the family. |
| Compound-complex | 2+ independent + 1+ dependent | Although the power failed, the generator started, and the monitors stayed on. |
Signal words: a FANBOYS word between two full clauses points to compound; a dependent marker points to complex. A long sentence is not automatically complex. The first example has a double subject (nurse and aides) but only one clause, so it is simple.
Walk-through: in the last example, "Although the power failed" opens with a marker, so it is dependent. "The generator started" and "the monitors stayed on" can each stand alone. That is two independent plus one dependent, so the sentence is compound-complex.
3 What makes a fragment, and how do you fix it?A fragment is a group of words punctuated as a sentence that lacks a subject, a verb, or a complete thought. 1 min
A fragment is a group of words punctuated as a sentence that lacks a subject, a verb, or a complete thought.
| Fragment type | Incorrect | Fixed |
|---|---|---|
| Dependent clause alone | Because the lab was closed. | Because the lab was closed, we sent the sample out. |
| -ing phrase alone | Hoping to leave on time. | Hoping to leave on time, she charted during her break. |
| No main verb | The new scanner in the hallway. | The new scanner in the hallway is broken. |
| "Such as" phrase alone | Such as gloves and masks. | Restock the supplies, such as gloves and masks. |
Quick test: read the word group alone, with no sentence before it. If it leaves you waiting for more, or has no subject–verb pair without a marker in front, it is a fragment.
4 How do you fix run-ons and comma splices?Two independent clauses always need a strong joint between them. 1 min
Two independent clauses always need a strong joint between them.
- Run-on (fused sentence): The printer jammed the nurse refilled the tray. Nothing joins the clauses.
- Comma splice: The printer jammed, the nurse refilled the tray. Only a comma joins them.
| Fix | Corrected sentence |
|---|---|
| Period | The printer jammed. The nurse refilled the tray. |
| Semicolon | The printer jammed; the nurse refilled the tray. |
| Comma + FANBOYS | The printer jammed, so the nurse refilled the tray. |
| Semicolon + transition + comma | The printer jammed; therefore, the nurse refilled the tray. |
| Make one clause dependent | When the printer jammed, the nurse refilled the tray. |
Classic wrong answer: The printer jammed, however, the nurse refilled the tray. However is not a FANBOYS word, so this is still a comma splice.
Common mistakes
The traps students fall into most. Read these before you practice.
Watch out: Length does not decide the type: a long sentence with one subject-verb core is still simple, and a short one can be a run-on.
Watch out: A long string of words with no main verb, or one that starts with because, is still a fragment, even if it feels complete.
Watch out: Adding however with only commas does not fix a comma splice; however needs a semicolon before it.
Watch out: Watch for fixes that create a new error: splitting a sentence can leave a because clause standing alone as a fragment.
Watch out: Two verbs sharing one subject (the aide checked and restocked) is still one clause, not a compound sentence.
How to remember it
Think of every independent clause as a full train car that needs a strong coupling to the next one. The strong couplings are a period, a semicolon, or a comma plus FANBOYS. A comma alone is too weak. A dependent clause is a car with no engine that must hook onto a full one.
Self-check:
- Name the type: "When the shift ended, the aides left."
- Fix two ways: "The clinic was full, we waited outside."
- Turn "Since the badge reader was broken." into a complete sentence.
Show answers
- Complex.
- "When the shift ended" opens with a marker, so it is dependent.
- "The aides left" can stand alone, so it is independent.
- One independent plus one dependent makes a complex sentence.
- Any two of these work:
- Period: "The clinic was full. We waited outside."
- Semicolon: "The clinic was full; we waited outside."
- Comma + FANBOYS: "The clinic was full, so we waited outside."
- Make one clause dependent: "Because the clinic was full, we waited outside."
- Sample: "Since the badge reader was broken, we signed in at the desk."
- Since is a dependent marker, so the word group cannot stand alone.
- Hook it onto an independent clause with a comma.