Why commas matter

This time, the adjectives aren't interchangeable. If you reverse them, you can probably see why. This means they shouldn't be separated with a comma. The truth is, frozen yogurt is more than just an adjective followed by a noun. It's type of thing , like a miniature poodle , striped shirt , or even hot chocolate. All of these examples are made up of two words, but they represent a single thing.

If you separate them with a comma—or write them in a different order—the words lose their meaning. You might already know that an incomplete sentence is a fragment. When you begin a sentence with a fragment, it's called an introductory clause.

To learn more, check out our lesson on Fragments. It's perfectly OK to begin a sentence this way, then follow it with a complete thought. You just have to separate these thoughts with a comma. This makes the sentence easier to read, and it also tells the reader where to pause if needed.

In the example above, the thing before the comma while you were sleeping is a fragment; the thing after the comma I gave you a new haircut is a complete sentence. The comma is necessary only if the clause introduces the sentence. If the phrases were written in the opposite order, you wouldn't use a comma. What about expressions like luckily , however , and as you can see? It's more common to see these at the beginning of a sentence, but they can appear the end as well.

Unlike introductory clauses, they don't necessarily add anything new to the sentence. Regardless, they should always be separated by a comma. For example: I gave you a new haircut, as you can see. You should also use commas to separate nonessential clauses that appear in the middle of a sentence. A nonessential clause is something that adds meaning but that isn't completely necessary. In other words, if you took it out the sentence would still mean basically the same thing.

To find out if a clause is nonessential, try removing it from the sentence, then see how it sounds. The sentence above would still make sense if we removed the detail about the ascot. It would be: Steve is very tidy. If the clause was essential, we wouldn't be able to remove it. Try this sentence instead: Men who wear ascots are very tidy. If we take out the detail about the ascot, we're left something slightly different: Men are very tidy.

This is far too general to be true—after all, some men are really sloppy. This is how you know the clause is essential to the sentence's meaning. As you gain more experience with commas, you'll run into cases when your judgment matters more than ever. These cases are more difficult to define, but they build on the rules we just discussed.

For instance, some sentences end with a type of fragment called a free modifier. This is just a fancy word for something that clarifies or relates to another part of the sentence. When you use a free modifier like this, always separate it with a comma. Other sentences end with a distinct pause , followed by something more ambiguous. That final beat could be the name of the person you're talking to, a statement of confirmation, or a single word.

Whatever it is, that beat also should be separated by a comma. Below are two sentences that include a series of commas—one is correct, and the other is not. Use what you just learned to decide which one is correct, then click the dots to see if you're right! Here, an essential clause has been mistaken for a nonessential clause. The kitten was cute. You can often spot them because they begin with conjunctions or prepositions , like after, as, before, if, since, that, though, unless, until, when, and while.

After I visited the animal shelter. You can join one or more independent clauses to form a compound sentence, and independent clauses can be added to dependent clauses to form complex sentences. A comma splice happens when you connect two independent clauses with a comma instead of a conjunction or other appropriate punctuation like a semicolon. The kitten was cute, I wanted to take it home with me.

The kitten was cute is an independent clause. It can stand alone as a sentence. The same thing applies to I wanted to take it home with me. The comma incorrectly splices the two sentences together. I wanted to take it home with me. The kitten was cute, so I wanted to take it home with me. The kitten was cute; I wanted to take it home with me.

In the example above, you could use therefore in place of the semicolon. Those clauses are directly related. When in doubt, let clarity be your guide.

Conjunctions are words that link other words, phrases, or clauses together. When should you use commas with conjunctions? The pet store was fresh out of kitten toys, so I had to improvise. The pet store was fresh out of kitten toys; therefore I had to improvise.

The serial comma should always be used where it is needed to avoid confusion. Can you see the ambiguity in the example below? In this situation, the serial comma needs to be used. Otherwise, depending on the chosen style guide, it is considered optional. Still, not using the serial comma is relatively uncommon in American English, except in newspapers and magazines.

Another type of relationship between ideas that writers signal to readers with a comma is that of accumulation. Occurring at the end of a sentence, cumulative clauses hook up to a main clause and add further information. They often include additional descriptive details. Commas should also be used when writing dates. There should always be a comma between the day and the year and between the year and the rest of the sentence. Even when the date is not a dependent clause, as it is in the previous example, the last item in the date should be followed by a comma.

Calling in sick for work, Beth hoped her boss would not suspect anything : The title contains a verb in its introductory phrase, which warrants a comma before the final clause.

The comma serves a variety of grammatical functions, including to indicate pauses or set off introductory phrases, as in the title example. Comma usage errors fall into two categories: using unnecessary commas and failing to use necessary commas. A comma splice occurs when two independent clauses that is, two complete sentences are joined only by a comma. In those situations, an acceptable form of punctuation would be a semicolon or a period.

For example:. You can make two complete sentences by inserting a period. This is the strongest level of separation. You can use a semicolon between the two clauses if they are of equal importance; this allows your reader to consider the points together. You can use a semicolon with a transition word to indicate a specific relation between the two clauses; however, you should use this sparingly.

You can use a coordinating conjunction following the comma, and this also will indicate a relationship. Or, you can add a word to one clause to make it dependent. The independent clauses may not have any punctuation separating them, or they may have a coordinating conjunction between them, but without the comma that needs to accompany it to separate the independent clauses.

Fixing run-on sentences is very similar to fixing comma splices. You can use a coordinating conjunction and a comma, and this also will indicate a relationship. Privacy Policy. Skip to main content. Overview of English Grammar: Punctuation and Mechanics. Search for:. Introduction to Commas The comma is a punctuation mark that indicates a slight break, pause, or transition. Learning Objectives Identify situations that require commas.