
Sentence fragments are incomplete sentences, like these:
- And a cup of coffee.
- A long time ago.
- Showing that teenagers have undeveloped prefrontal cortexes.
You can make these into complete sentences by adding in the missing part:
- I’d like an all-day breakfast, please, and a cup of coffee.
- A long time ago, there was an old woodcutter.
- Jay Giedd conducted a study showing that teenagers have undeveloped prefrontal cortexes.
The last example is a very common type of sentence fragment seen in essays. Starting a complete grammatical sentence with an -ing word is possible, but it’s more often a red flag that a sentence fragment is coming. If you find yourself starting a sentence with an “-ing” word, ask yourself whether it’s a sentence fragment, and how to turn it into a complete sentence.
There’s a more detailed explanation of what makes something a complete grammatical sentence, what makes a sentence fragment, and how to fix them here: https://www.grammarly.com/blog/sentence-fragment/
