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  Writing for Business and Pleasure

  Copyright 2014 by
Stephen Wilbers

Column of the Month



If you've never really understood when to use a comma with which and when to omit it with that, this column might do the trick for you.


First published August 22, 2005

Can’t get over that nonrestrictive comma

By Stephen Wilbers

I’ve been thinking about nonrestrictive commas lately. I just can’t get them off my mind.

Many writers don’t use them. Rather than include the comma in a sentence such as “I helped raise $100,000 for the new Minneapolis Public Library, which opened in May 2005,” they leave it out.

Omitting or misusing the nonrestrictive comma is one of the last major errors many writers eliminate from their writing. It’s a persistent error, one that lingers even in the text of otherwise competent writers.

Imagine how you’d feel if you were a driving instructor and you noticed that three-quarters of the drivers on the road weren’t using their turn signals. You’d feel awful.

I’ve tried teaching writers when to use commas with nonrestrictive clauses. I’ve tried every approach I could think of. Nothing seems to work. So I’m trying something new.

I’ve created a PowerPoint presentation explaining the rule, and I’m posting it on my website. Here’s a preview:

Nonrestrictive clauses are generally introduced by which.

Restrictive clauses are generally introduced by that.

Both nonrestrictive and restrictive clauses, however, may be introduced by who.

Nonrestrictive clauses are nonessential. They may be deleted from a sentence without changing its meaning.

Nonrestrictive clauses do take commas.

Restrictive clauses are essential. Deleting them changes the meaning of the sentence. They are said to be “restrictive” because they “restrict,” limit, or define the thing they refer to, as does the that clause in this sentence: “The quality that impresses me most is honesty.” Remove the clause and you have a different meaning.

Restrictive clauses do not take commas.

Imagine two men walking toward you: “The man who is wearing a white hat is 102 years old.” The who clause is telling you which man is wearing the hat. Omitting the clause would alter the meaning of the sentence, so the clause is restrictive or essential to the meaning of the sentence. No commas.

Now picture only one man. He’s wearing a black hat, and he’s 90 years old: “That man, who is wearing a black hat, is 90 years old.”

Note the commas marking the who clause. The clause merely describes, rather than defines, the person or thing it refers to, so it is said to be “nonrestrictive” or nonessential to the sentence. Deleting it would not change the meaning. Nonrestrictive clauses are marked with commas.

Here are two hints to help you recognize nonrestrictive clauses and phrases:

Hint no. 1: If parentheses can be placed around the clause or phrase, it’s nonrestrictive. Use commas.

Hint no. 2: If the words “by the way” can be inserted after which or who, it’s nonrestrictive. Use commas.

Remember: Nonrestrictive clauses (which by the way are nonessential) take commas.

So why not go to my website and take a look? As you click on the little arrow, open your subconscious mind to the words and examples that appear on your screen. Let them sink in. Learn when to use nonrestrictive commas. Knowing will help you write more clearly, and it will make me happy.


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