Commas & Restrictive Clauses

It's time for a strictly lesson post!

See what I did there?" 'Strict'ly? We're about to study restrictive and non-restrictive clauses? *wink*

A restrictive clause limits the possible meaning of a preceding subject or object. In this way, the subject/obj. is a specific subject/obj., and the added clause defines that sub./obj. to be a certain sub./obj. as opposed to another one.

Let's take some examples and break them apart:

Justin swung the baseball bat that was made out of wood and hit a home-run.

Non-Restrictive Clause:

Justin swung the baseball bat, which was made out of wood, and hit a home-run.

Take a good look at the italicized words. In the restrictive clause (first) the clause "that was made out of wood" is significant in the sentence because it defines which baseball bat Justin swung. You can usually tell it's a restrictive clause because of the use of the word 'that', which is associated with restrictive clauses.

On the contrary, the non-restrictive clause has commas due to the appositive phrase "which was made out of wood". You can tell from the wording and the commas that the fact that the baseball bat was made out of wood isn't really an important detail. It's important not to write a restrictive clause in the wrong way and use commas where they aren't meant to be used.

For example, the following sentence would be grammatically incorrect:

Justin swung the baseball bat, that was made out wood, and hit a home-run.

The commas placed before and after the italicized words are unnecessary. They should be omitted in order for the sentence to be correct. Alternatively the sentence could be altered to make the italicized clause an appositive phrase, which would change the significance of the clause.

Similarly, one should not confuse an appositive phrase like the following for a restrictive clause:

Justin swung the baseball bat, smashing the ball as hard as he can, and hit a home-run.

The italicized phrase is not saying which baseball bat Justin used, but rather it is describing how Justin swung--Justin swung very hard, smashing the ball as hard as he could. This is a correct appositive phrase and so the commas SHOULD be kept here.

If you're unfamiliar with appositive phrases please wait for a new blog post on the matter or google it until we cover it here on the blog.

With that I hope you now understand what restrictive clauses are (as opposed to non-restrictive clauses) as well as when to use and not use commas with them. To wrap things up:

- Don't use commas with restrictive clauses
- Do use commas with certain types of non-restrictive clauses, such as appositive phrases
- Make sure you are familiar with the definitions of such things and how they work so you don't confuse one type of clause with another
- Sound out sentences with the commas and see if it sounds right--you can often figure out whether a comma is being used right just by saying the sentence out loud!