Its Time to Improve You’re Grammar: “That vs. Which”

Dear grammar lovers: those are dangling fingers, not participles...
Dear grammar lovers: those are dangling fingers, not participles…

In the world of grammar, certain little words can make a big difference in your sentences. Proper usage of the words that and which trips up many an unsuspecting person. Some of you may believe that and which are interchangeable but, in fact, they are not.

Additionally, I come across more and more articles these days dissuading people from even contemplating the use of the word that. Many experts deem it a mediocre piece of filler. I’m all for crisp, clean writing, but that does legitimately reside within my beloved Merriam-Webster’s. So if you’re going to use it, you should use it well.

Are you ready for another easy-to-digest grammar lesson cushioned by my trademark sense of humor? Here we go!

“That” and “Which” Are Used to Introduce Clauses (No Relation to Santa): The key to correct use of these innocent-looking words in your written communication is knowing what type of clause each introduces in a sentence. While that introduces a restrictive clause, which is the function word of choice when introducing a nonrestrictive (or parenthetical) clause.

I realize you just now might have experienced a bad flashback from your high school English class (freshman year!), so fear not – I will remove the claws from my clauses.

A Clause Is a Clause, of Course, of Course…: I desperately hope the sainted Mister Ed isn’t rolling over in his final resting pasture as a result of my bad joke. Simply put, a restrictive clause is essential to the meaning of a sentence. If you delete a restrictive clause, you will change the intended meaning of your sentence.

On the flip side, a nonrestrictive clause doesn’t impact a sentence’s basic meaning, so if you leave it out, the sentence still makes sense. Fortunately, there’s a clever tip to help you grasp the difference between these two types of clauses: Nonrestrictive clauses introduced by which are either surrounded by a set of commas or preceded by a comma. Some eclectic examples for both types of clauses follow…

Use That to Introduce a Restrictive Clause (So That’s That):

Roller coasters that don’t have seat belts or security harnesses are a fast, sure ride to death. (If you remove “that don’t have seat belts or security harnesses,” the sentence dooms all roller coaster riders to assault by a deadly amusement-park ride.)

Networking events that don’t provide any food are a waste of my time. (If you remove “that don’t provide any food,” the sentence rudely implies I don’t bother with such gatherings…)

All cars that are red usually get pulled over by the police or state troopers for speeding. (If you remove “that are red,” your local police force are the masterminds behind a lucrative money-making scheme!)

Use Which to Introduce a Nonrestrictive Clause (Which Is Which?):

My smart phone, which is an iPhone 4S, is a convenient device for entertaining small children and annoying technophobes. (If you remove “which is an iPhone 4s,” the sentence retains its original message. This is good news for kids and bad news for people who think an apple is merely a piece of fruit.)

Derek refuses to listen to anything but Paris Hilton tunes in his office, which causes my brain to temporarily misfire. (If you remove “which causes my brain to temporarily misfire,” Derek doesn’t care, and he will continue to enjoy bad music while he works.)

The elusive Mr. Gold LEGO minifigure, which is available for purchase on eBay at obscene prices, is desired by many LEGO fanatics. (Those d@mn adult scalpers are causing a lot of trouble for parents all over the world…)

Bonus Grammar Tip, Gentle Readers: If you’re modifying a person (instead of an object or thing) in a sentence, you should always use the word who (never that). Here’s what I mean:

Ermengarde is the girl who chews all the ice cubes in her Long Island Iced Tea.


The next time you find yourself about to use either that or which before a clause, try the restrictive-versus-nonrestrictive litmus test. You’ll see just how easy it is to know when to use each word in the proper context. Grammar Girl’s (Quick and Dirty) tip is “to remember that you can throw out the ‘whiches’ and no harm will be done.”

This blog post, which I crafted for you with love, is just one more notch in your grammar belt. However, written communication that doesn’t demonstrate a command of your native language should be a criminal offense. Until next time, my grammar goslings

Lori Shapiro is the owner of By All Writes LLC, a business-to-business (B2B) writing, editing, and research company in Marlton, New Jersey. She revels in shielding her clients from the pain of writing their own print and web marketing copy. Call her (856-810-9764) or email her ( for a no-obligation project quote today!

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