Which is a run-on sentence?
The conductor took tickets from everyone on the train. Mabel is from Greenpoint now she lives in Springdale.
A sentence is a group of words that forms a complete thought. It has both a subject and a verb.
My friends walk along the path.
A run-on sentence is made up of two sentences that are joined without end punctuation or with just a comma.
I knocked on the door it opened.
It started raining, we ran inside.
To fix a run-on sentence, separate it into two sentences. Add end punctuation after the first sentence, and capitalize the second sentence.
I knocked on the door. It opened.
It started raining. We ran inside.
You can also fix a run-on sentence by rewriting it as a compound sentence. A compound sentence is two sentences joined by a comma and a conjunction such as and, but, or, or so.
I knocked on the door, and it opened.
It started raining, so we ran inside.
Mabel is from Greenpoint now she lives in Springdale is a run-on sentence. It has two sentences that are joined without end punctuation: Mabel is from Greenpoint and Now she lives in Springdale.