Restricted Diet
By Angela Arlia

’m sure you are wondering how diet relates to grammar. Or you are wondering if perhaps you didn’t select the wrong link on our fantabulous site. As long as you are questioning and thinking, I might as well get started.

Often we try to control our diets and watch what we eat. The things that go in our mouths are sometimes not essential to our well-being. Oh, we like to think that the wonderful snicker doodle cupcake is necessary to our humanity but it isn’t. (I’m sorry to be the one to say it but someone had to.)  As any good doctor and most moms will tell you, healthy living means that we restrict our diets and eliminate food items that are not beneficial to our health.
Grammar works in much the same way, in the sense of restrictions, that is. There are words that we use every day. Some words are essential:  verbs to show action and being; nouns to tell us who or what is doing the action or being. Other words are totally superfluous and aggravating, such as “like” and “um” and “you know?” (Don’t worry, I’ll talk about those gems in another fantabulous Grammarian column in the near future.)

A couple of words that are essential but often confusing are “that” and “which.” When do you use them in a sentence? What is their purpose? In a nutshell, we use these two wonderful little words to add more information to a sentence, usually to qualify something we’ve said already in the first part of the sentence. When the information being added is essential to the meaning of the sentence, we should use “that.” When the additional information isn’t essential or important to the sentence it’s describing, you can use “which.”  In other words, without “that” we’d have no clue what is going on, while “which” we can take or leave.

I realize this is a little confusing in the abstract, so here are some examples:

1) It is essential that I write grammar columns because too many people make grammar mistakes!

You ask yourself, “What is essential?”  If the answer is something you absolutely must know, use “that” to complete the sentence.

2) The grammar article, which I wrote, is chock full of essential information.

The little bit between the commas there isn’t really that important, is it? Oh, to me it is. But in the big scheme of meaning, it isn’t. The sentence would be perfectly complete and meaningful without it. Indeed, if I were to leave that piece out, the meaning of the sentence wouldn’t change at all.

Some more examples so you can test this out for yourselves.

3) The package, which contained a fun-filled vacation to Iowa, was still left unclaimed at the post office. (Does this change the meaning of the sentence? Not really.  Even without that “aside” in the middle, we’d know that the package was languishing at the post office.)

4) The package that smelled of sulfur was found in the basement. (The sentence could make sense without the information about the smell but it adds more information—it changes the meaning of the sentence. Hence the use of ‘that’ instead of ‘which’)

So to sum up:  When adding qualifying or descriptive information to a sentence, use “that” if the bit you’ve added changes the meaning of the sentence.  If the sentence could get along fine and be just as easily understood without the extra information, go with “which.”  I’m sure you’ll feel healthier as a result.