A sentence expresses a complete thought and ends with a full stop, question mark, or exclamation mark. It is never correct to join two sentences by a comma.
For example:
'My mother came into the room where I was watching television, she told me to go and do the washing up.'
These are two separate thoughts and should be written:
'My mother came into the room where I was watching television. She told me to go and do the washing up.'
Alternatively they can be linked by a conjunction:
'My mother came into the room where I was watching television, and she told me to go and do the washing up.'
Another possibility is to extend the sentence:
'My mother came into the room where I was watching television, she told me to go and do the washing up, and I refused.'
run-on sentence
a comma splice. This occurs when two independent clauses are incorrectly connected by a comma without a coordinating conjunction. This mistake can be corrected by using a semicolon, period, or conjunction to properly separate the clauses.
It's called a run-on comma splice.
Fragments are incomplete sentences that lack a subject or verb. Run-ons are two or more independent clauses incorrectly joined together without proper punctuation or conjunctions. Comma splices occur when two independent clauses are incorrectly connected with a comma instead of a conjunction or appropriate punctuation.
He won, he had the best score. This is an incorrect or comma splice sentence -- two distinct ideas joined incorrectly by a comma. Either rewrite as two sentences, or change the comma to a semicolon.
Using a comma to join independent clauses that could stand alone as sentences
A run-on sentence occurs when two independent clauses are connected without proper punctuation or conjunctions. A comma splice, on the other hand, happens when two independent clauses are incorrectly joined with a comma but without a coordinating conjunction. Both errors result in choppy or confusing sentences.
contains two or more simple sentences joined by a comma and a coordinating conjunction or by a semicolon> and, but, nor, or for.
A comma splice is characterized by two independent clauses that are incorrectly joined by a comma. This error occurs when two complete thoughts are separated by a comma without the appropriate conjunction or punctuation.
A comma splice is when a two complete sentences are separated by a comma, without a conjunction. This makes it gramatically incorrect. A run-on sentence continues on and on with no clear predicate.
This is known as a comma splice. It is considered a punctuation error as it incorrectly joins two independent clauses without a coordinating conjunction or appropriate punctuation. To correct a comma splice, you can either use a semicolon, separate the clauses into two sentences, or add a coordinating conjunction like "and," "but," or "or."
A compound sentence becomes a comma splice when two independent clauses are incorrectly joined together with just a comma, without a coordinating conjunction or proper punctuation. This creates a run-on sentence where the two ideas are not properly connected.