What is this skill?
A complete sentence has a subject (who or what it is about) and a verb (what happens), and it expresses a whole thought. A fragment is missing a piece, so the reader is left hanging: "When the bell rang." tells us when, but not what happened. A run-on is the opposite problem. Two whole sentences are jammed together with no break or joining word, such as "The movie was long it was also boring."
In this practice children pick the complete sentence from three choices (The children ran down the hill, not Running down the hill), spot which one is a fragment ("After the game ended.") or a run-on ("Maya likes art Jamal likes music."), and choose the best fix. Fixes for a run-on include a period and a new sentence, or a comma and a joining word, as in "The sun was hot, so we went swimming." Fixes for a fragment add the missing part: "Under the old oak tree" becomes "We had a picnic under the old oak tree." A group of yes-or-no questions gives a sentence and asks whether it is complete or a fragment or run-on. Not every short sentence is a fragment, and the bank includes a one-word one that is complete: "Hurry!"
Why it matters
Sentence structure is the foundation of clear writing. A fragment or a run-on makes the reader stop and work out what was meant, and by fourth grade teachers expect writing that does not make them do that.
Children also write the way they talk, and speech is full of fragments and strung-together thoughts. Learning to see the edges of a sentence is the step that turns talk into writing.
Fixing run-ons helps children combine ideas well. A comma and a joining word such as and, so or but shows how two ideas relate, and that is a more advanced skill than just using a period.
Common mistakes
- Thinking that a long group of words must be a sentence. "Jumping over the puddles" has plenty of words and still has no one doing the jumping. Ask "who or what?" and "did what?"
- Mistaking a "when" or "because" start for a whole thought. A group of words that begins with after, when or because feels as though it should end, but it needs a second part, as in "After the game ended."
- Fixing a run-on with only a comma. "The sun was hot, we went swimming" is still a run-on, called a comma splice. A comma needs a joining word like so, and the practice shows the right answer next to this wrong one.
- Calling every short sentence a fragment. "Hurry!" is short, but the subject (you) is understood and it is complete.
How to help at home
- Read a sentence aloud and ask "Does it feel finished?" If you stop and a child wants to hear more, it is probably a fragment.
- Take a run-on from your child's own writing, with gentle praise for the ideas, and find the spot where one thought ends and the next begins. Add a period or a joining word there.
- Play "finish my thought." Say a fragment like "Under the old oak tree" and have the child finish the sentence.
- Read the sentences from the free worksheet aloud with a pause at each period. Your ear will catch many of the problems.
Worked examples
These are real questions from the Tutorsaurus fragments and run-ons practice, with the answers worked out.
Example 1
Which one is a complete sentence?
Choices: Running down the hill., The children ran down the hill., Down the hill fast.
Answer: The children ran down the hill. A complete sentence needs a subject and a verb. The children (subject) ran (verb).
Example 2
Is this a complete sentence?
Noah called his grandma, and she told him a story.
Answer: Complete. Two complete thoughts are joined correctly with a comma and the word "and."
Example 3
Which best fixes this run-on? "The sun was hot we went swimming."
Choices: The sun was hot, so we went swimming., The sun was hot, we went swimming., The sun was hot we went, swimming.
Answer: The sun was hot, so we went swimming. A comma plus a joining word like "so" fixes the run-on. A comma by itself is not enough.
Printable worksheet (PDF) — one page of questions from this practice that work on paper, easier ones first, with an answer key on page 2. Free to print, no sign-up.