Commas Rules

Commas have three main functions: to separate clauses, to join dependent clauses, and to avoid confusion.

This lesson is a part of Onsego GED Prep.

Video Transcription

On the language test, the grammar part is presented as a mini story with incomplete sentences. Your task is to choose the correct part of a sentence to complete it. Many times, you’ll need to choose the part with the correct comma usage.

Let’s take a look at the most common comma rules you’ll need to know for the test!

1. Using a Comma After the Start of a Sentence

A common mistake people make is forgetting to use a comma after introductory words or phrases. This is something the language test checks often.

Here’s the rule:

If a sentence starts with a starter word, phrase, or clause, you need a comma right after it.

For example:

Recently, we received many alerts related to lost luggage.

Sadly, the game was canceled.

Finally, my sister passed her driving exam.

However, I decided to go swimming.

Why do we use a comma here? It separates the introduction from the main idea of the sentence and makes everything easier to read.

Here’s a simple trick to remember this:

If you read the sentence out loud, you’ll notice a natural pause after the introductory part. That pause is where the comma goes!

Let’s try a quick check:

Where would you put the comma in this sentence?

We decided to go to the park. It was a warm day, and the sun was shining. However I have a feeling it could change so I decided to take the umbrella.

And now, let’s add a comma after however.

Here’s the corrected version:

We decided to go to the park. It was a warm day, and the sun was shining. However, I have a feeling it could change, so I decided to take the umbrella.

See how the comma after “However” makes the sentence flow better?

The more you practice, the more natural this will feel. And remember, introductory words like “however,” “recently,” and “finally” always need a comma after them!

2. Commas for Additional Information

Another common rule you’ll need to know is using commas to set off extra information — also called nonessential information.

Here’s what that means: Sometimes, we add details to a sentence that aren’t necessary to the main point. These details need to be separated by commas.

For example:

My friend, who is a great cook, made dinner for us.

The park, which is usually quiet, was noisy today.

Without those extra details, the sentences still make sense:

My friend made dinner for us.

The park was noisy today.

Here’s a quick trick to help you decide if commas are needed:

Remove the extra information from the sentence. If the sentence still works without it, then use commas to separate the extra part.

Let’s test this rule:

Where do you add commas in this sentence?

My brother who lives in New York is visiting us next week.

Think about it…

The correct version is:

My brother, who lives in New York, is visiting us next week.

Why? Because “who lives in New York” is extra information. It gives more detail, but the sentence makes sense without it.

3. Using Commas in Lists

You probably already know that commas separate items in a list. But there’s a specific comma rule that the GED test checks — and it’s easy to forget.

When listing three or more items, you need to place a comma before the conjunction (like “and” or “or”).

For example:

I need to buy bread, milk, sugar, oranges, and eggs from the store.

Notice the comma before “and”? That’s called the serial comma and it’s required in formal English.

Here’s another example:

When I want to relax, I watch movies, read books, ride a bike, or swim.

Did you see the comma before “or”? That’s the serial comma again.

Why does this matter?

The GED test will check whether you know to use this comma before the conjunction in a list of three or more items.

Here’s a trick to help you remember it:

When you see a list, ask yourself — Did I add a comma before “and” or “or”? If not, you’re missing the serial comma.

The bottom line? Always add a comma before the conjunction in a list. It’s a formal rule, and the GED test expects you to know it.

Now it’s time to practice what you’ve learned. The more you practice, the easier it will get! Keep going, and you’ll feel more confident when you see these types of questions on the GED test.

Last Updated on October 19, 2025.