From time to time readers contact me with grammar questions. Today’s column is dedicated to answering some of those letters.

Dear Dr. Palmer,

I don’t understand the rules for using “that” and “which.” I remember learning that they are not always interchangeable, but I don’t understand how I’m supposed to tell the difference between them. They seem the same to me. Would you explain those please?

Perplexed in Prospect

Dear Perplexed in Prospect,

You ask a very good question because it can be difficult to understand the difference between “that” and “which.” This is one of those rules that has a lot more to do with writing than with speech. Before I explain the rule, however, I want to point out the difference between a sentence such as “The bananas I bought last week, which were on the table, were perfect for banana bread” and “I was saving the bananas that were on the table for banana bread.” In the first sentence the information about the bananas being on the table is extra information and is not essential to the sentence. In the second sentence the information about the bananas being on the table is essential because it was those very bananas that I was going to use to make banana bread. (They disappeared and now I have to go get more. Who ate them?)

Making this kind of distinction between essential and non-essential information is often more important in writing than in speech. When one communicates in writing, there is rarely a shared visual scene, and there is no tone of voice or body language to fill in possible gaps in communication. So, the rule governing the use of “that” and “which” is as follows: if you are describing information that is absolutely necessary to the sentence use “that”; if you are including information that is extra and not really essential for comprehension, then use “which.”

If it helps, think about it like this. “That” is used for essential information much like an elegant black cocktail dress requires a pair of sharp- looking black heels.

“Which” is for accessories that aren’t essential but make the ensemble look even better, like the right belt or the perfect earrings. The sentence with “that” will not require commas, but the sentence with “which” will. Here are several sentences you can use to test yourself. Notice that I have left out the commas on purpose. The answers may be found at the end of the column

1. Grandma’s apple cake [ ______ has nuts] won a blue ribbon at the fair. (Grandma entered just one cake in the competition.)

2. Grandma’s cake [ ______ won a blue ribbon at the fair] had walnuts in it. (Grandma is famous for many cakes. I’m referring to a specific cake.)

3. The book [ ______ costs more than $100] is required for the class. (There are a several books, ranging in price, on the shelf in front of you.)

4. The book [ ______ costs more than $100] is required for the class. (There is only one book for the class, and it is expensive.)

5. The vintage John Deere tractor [ ______ was stored in the back lot] has been stolen. (The fact that the tractor has been stolen is the most important information here.)

6. The John Deere tractor [ ______ was stolen] had been parked in the back lot. (This sentence refers to a specific tractor, the one that was stolen.)

Dear Julia,

My new office assistant has been on my case recently because I say “between you and I.” It’s a little annoying because I’m her supervisor. She says it is supposed to be “between you and me.” Is this true and, if so, why? I think “between you and I” sounds better, plus I hear the president of our organization say it all the time when he makes announcements, speeches, etc.

Sincerely,

Jackie

Dear Jackie,

There are a lot of educated people who say “between you and I,” but don’t be fooled by all their years of education. They are confused, and it sounds as if you might be as well. According to the rules of standard English, you are supposed to say “between you and me.” What has happened is that you have probably been corrected for using “me” inappropriately (at least according to the rules for standard English). For example, it is not grammatically correct in standard English to say “Me and Fred are going to the party tonight.” In this case you should use “I” as in “Fred and I are going to the party tonight.” All of these legitimate corrections have probably made you (and your president) afraid to use “me” where it is absolutely correct to do so. Unfortunately, you may now associate “I” with “proper” or “better” grammar and therefore extend the uses of “I” to too many contexts. It is a matter of function. “I” is a subject and “me” is an object. The preposition “between” requires the object “me” and not a subject. So your administrative assistant is absolutely right to remind you to say “between you and me.” My Aunt Eliza used to teach her students a little rhyme: Between you and me, that’s the way it’s supposed to be. Between you and I, what a terrible thing to cry. Hope that helps, and give your administrative assistant a raise.

If there is a particular grammar point that you find troubling, write in and ask. My guess is that many other people find that point confusing as well. You may send your questions to me at jpalmer@hsc.edu or to P.O. Box 177, Hampden-Sydney College, 23943.

Answers to “that/which” sentences:

1. Grandma’s apple cake, which has nuts, won a blue ribbon at the fair.

2. Grandma’s cake that won a blue ribbon at the fair had walnuts in it.

3. The book that costs more than $100 is required for the class.

4. The book, which costs more than $100, is required for the class.

5. The vintage John Deere tractor, which was stored in the back lot, has been stolen.

6. The John Deere tractor that was stolen had been parked in the back lot.

Julia Palmer is an associate professor of modern languages at Hampden-Sydney College. Her email address is jpalmer@hsc.edu.