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.
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.
It's called a run-on comma splice.
Using a comma to join independent clauses that could stand alone as 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 two independent clauses are incorrectly joined with just a comma. A run-on sentence occurs when multiple independent clauses are joined together without proper punctuation or conjunctions. Both mistakes can lead to confusion and should be avoided in writing.
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 consists of two independent clauses joined by a comma and a coordinating conjunction.
An example of two sentences written as one sentence and usually separated by a comma is "I went for a run in the morning, it felt refreshing." This structure is called a comma splice, which combines two independent clauses in a single sentence.
A compound sentence often consists of two independent clauses joined by a comma and a coordinating conjunction.