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Skill lesson · Language

Sentence structure

Fragments, run-ons, and comma splices, how to join two ideas correctly, parallel structure in lists and pairs, and the wordy or awkward sentence the HSPT asks you to improve.

Why it matters on the HSPT

The composition part of the Language section asks which sentence is written correctly, which is clearest, or which does not belong. Sentence structure decides most of those. The test's wrong choices are fragments that sound like sentences, splices that sound smooth, and lists whose items do not match. The right answer is usually the plainest sentence with one subject, one verb, and nothing dangling.

The rules

A sentence needs a subject, a verb, and a complete thought. The dog barked is a sentence. Barking at the mailman is not; there is no subject and no main verb. When the dog barked is not either; it is a complete clause that depends on something else, so it leaves the reader waiting.

Fragments are usually a dependent clause standing alone, starting with words such as because, although, when, while, if, since, until, after, before, or a phrase with an ing verb and no main verb. Fix a fragment by attaching it to the sentence next to it or by giving it a main verb.

Run-ons and comma splices. Two complete sentences cannot sit together with nothing between them, and a comma alone is not enough. The game ended everyone left is a run-on; the game ended, everyone left is a splice. Three fixes: a period, making two sentences; a semicolon, keeping them close; or a comma plus and, but, or, so, yet, for, or nor. A fourth fix is to make one of them dependent: when the game ended, everyone left.

Words that are not joiners. However, therefore, then, also, and meanwhile do not join sentences. It rained, therefore we stayed in is a splice. Use a semicolon or a period before however-type words, and a comma after them.

Parallel structure. Items joined by and, or, or a list must share a form: nouns with nouns, ing words with ing words, to-verbs with to-verbs. He wanted to run, to jump, and swimming is broken; to run, to jump, and to swim is parallel. Pairs such as either and or, neither and nor, and not only and but also need matching forms on both sides.

Wordiness and awkward order. Among choices that are all grammatical, the test prefers the one that says it once, in natural order, without repeated words. Due to the fact that is because. At this point in time is now. A sentence that circles before it lands is usually the wrong choice.

Sentence variety is not the test. The composition items do not reward long or fancy sentences. They reward the clear one.

Worked examples

Example 1

Which of the following is a complete sentence?

A. Because the library closes early on Saturdays.

B. Running down the hallway toward the gym.

C. The library closes early on Saturdays.

D. Although we arrived before the doors opened.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: C: C

Sentence C has a subject, the library, a verb, closes, and a complete thought. A and D begin with words that make them depend on something else, and B has no subject and no main verb.

Example 2

Which sentence is written correctly?

A. The storm knocked out the power, we lit candles.

B. The storm knocked out the power we lit candles.

C. The storm knocked out the power, so we lit candles.

D. The storm knocked out the power, therefore we lit candles.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: C: C

Sentence C joins two complete sentences with a comma and a joining word, so. Sentence A is a comma splice, B is a run-on, and D is a splice because therefore is not a joining word.

Example 3

Which sentence is written correctly?

A. Jonah likes to draw, painting, and sculpting.

B. Jonah likes drawing, painting, and to sculpt.

C. Jonah likes drawing, painting, and sculpting.

D. Jonah likes to draw, to paint, and sculpting.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: C: C

Only sentence C keeps all three items in the same form. The others mix to-verbs with ing words, which breaks parallel structure.

Example 4

Which sentence is written correctly?

A. We waited an hour; then the bus came.

B. We waited an hour, then the bus came.

C. We waited an hour then the bus came.

D. We waited an hour, then, the bus came.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: A: A

Then does not join sentences, so a comma before it makes a splice, as in B and D, and nothing before it makes a run-on, as in C. The semicolon in sentence A is one of the correct fixes.

Example 5

Which sentence expresses the idea most clearly?

A. Due to the fact that it was raining, the game, which was scheduled, was canceled.

B. Because it was raining, the game was canceled.

C. The game was canceled owing to the fact of rain that was falling.

D. It was raining and because of this the scheduled game that was going to be played was canceled.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: B: B

Every choice says the same thing. Sentence B says it once, in order, with no repeated or padded phrases. The others add due to the fact that, which was scheduled, and other words that carry no meaning.

Example 6

Which sentence is written correctly?

A. Either you finish your homework or watching television is not allowed.

B. Either finish your homework, or you cannot watch television.

C. You can either finish your homework or watch television.

D. Either you finish your homework or television.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: C: C

Either and or must be followed by matching forms. In sentence C both are verbs, finish and watch. In A the two sides are a clause and an ing phrase, in B the comma and the mismatch of forms break the pair, and D drops the verb from the second side.

Example 7

Which group of words is a run-on sentence?

A. After the movie, we walked home and talked about the ending.

B. The movie was long, but nobody wanted to leave early.

C. The movie was long nobody wanted to leave early.

D. Although the movie was long, nobody wanted to leave early.

  1. A.A
  2. B.B
  3. C.C
  4. D.D
Show answer

Answer: C: C

Sentence C has two complete sentences with nothing between them. Sentence A has one subject with two verbs, sentence B joins two sentences with a comma and but, and sentence D makes the first idea dependent. All three are correct.

Common mistakes

  • Mistaking a long fragment for a sentence. Length is not the test. Look for a subject, a verb, and a complete thought.
  • Joining sentences with a comma alone. Add a joining word or use a period or semicolon.
  • Treating however and then as joining words. They are not.
  • Mixing forms in a list. Every item should match the first one.
  • Choosing the longest answer as the best one. The clearest sentence is usually the shortest correct one.

Practice

These rules decide most composition items and the splice questions in punctuation. The commas lesson covers the comma splice in detail, and the composition lesson covers paragraph-level questions.

Quick answers

What makes a group of words a fragment?

It is missing a subject, a verb, or a complete thought. Because the rain stopped has a subject and a verb but is not a complete thought; it leaves you waiting. Add the rest: because the rain stopped, we went outside.

What is the difference between a run-on and a comma splice?

Both jam two complete sentences together. A run-on has nothing between them; a comma splice has only a comma. Both are fixed the same three ways: a period, a semicolon, or a comma plus a joining word.

What does parallel structure mean?

Items in a list or pair should have the same grammatical form. She likes hiking, swimming, and to bike breaks the pattern; she likes hiking, swimming, and biking keeps it.

Updated Saturday, September 12, 2026