Commas are used in a variety of ways when punctuating clauses, phrases, and the four sentence types.
A common mistake you may have been taught about commas is that if there is a pause, you need to insert a comma. Instead, if you understand how commas work in sentences, then you can think through whether or not you need a comma.
There are many rules for commas. When you reread your paragraph, look closely at each comma to see if it fits into one of the following categories.
Use a comma after a word, phrase, or subordinate clause that precedes the main clause.
Use a comma in between items in a series. In formal academic writing, the last comma is usually preferred.
Comma after the first clause and before the coordinating conjunction in a compound sentence.
A comma splice is an error that occurs when you join two independent clauses with a comma. Instead, use a coordinating conjunction, period, semicolon, or a semicolon and adverbial conjunction.
Closely related to a comma splice is the fused sentence. This occurs when a writer joins two independent clauses with no punctuation. You fix a fused sentence the same way as you do a comma splice. Here is an example, using the same sentence above, of a fused sentence:
You would correct a fused sentence in the same way that you correct a comma splice.
When you can recognize independent clauses in your writing, you will begin to eliminate comma splices and fused sentences. Study Unit 4 again if you feel like you need some additional review.
When a subordinate clause appears at the beginning of a sentence, use a comma after the subordinate clause. However, if the subordinate clause appears at the end, you will usually omit the comma.
Subordination is yet another way to fix a comma splice or a fused sentence. Look at this example: