Apostrophes
Possession
With possessives, the apostrophe is used in combination with an s to represent that a word literally or conceptually possesses what follows it. Singular words whether or not they end in s, are made possessive by adding an apostrophe + s.
- a student’s paper
- one hour’s passing
- Illinois’s law
For plural words, we typically indicate possession simply by adding the apostrophe without an additional s. However, a plural that does not end in an s (e.g., bacteria), we would add an apostrophe + s.
- interviewees’ answers
- her professors’ office (an office shared by two of her professors; if it were just one professor we would write her professor’s office)
Contractions
A contraction is a shortened phrase. He will becomes he’ll, are not becomes aren’t, would have becomes would’ve, and it is becomes it’s. In all of these cases, the apostrophe stands in for the missing letters.
You may find yourself being steered away from using contractions in your papers. While you should write to your teacher’s preference, keep in mind that leaving out contractions can often make your words sound over formal and stilted. (And you shouldn’t eliminate contractions in your papers just to up your word count!)
Your versus You’re
Your versus You’re
- Your v. you’re
- Its v. it’s
- Their v. they’re
All three of these pairs are the same kind of pair: a possessive pronoun and a contracted version of a pronoun + to be (you’re = you are; it’s = it is; they’re = they are). These are easy to mix up (especially its/it’s) because—as we’ve learned—an apostrophe + s indicates possession. The best way to use these correctly is to remember that possessive pronouns never have an apostrophe: if there’s an apostrophe with a pronoun, it’s a contraction, not a possessive.
Acronyms and Numbers
In technical writing, acronyms and numbers are frequently pluralized with the addition of an apostrophe s, but this is falling out of favor, and there is typically no need to put an apostrophe in front of the s. Therefore, SSTs (sea surface temperatures) is more acceptable than SST’s when your intention is simply to pluralize.
Ideally, use the apostrophe before the s with an acronym or a number only to show possession (i.e., “an 1860’s law”; “DEP’s testing”) or when confusion would otherwise result (“mind your p’s and q’s”).
When talking about a specific decade the 1920s should be shortened to the ’20s. Notice that the apostrophe curls away from the numbers, indicating that the missing characters originally appeared prior to the apostrophe.
Practice
Read the following passage. Identify any errors with apostrophes. Type the corrected words in the text frame below:
Thanks to NASAs’ team of sniffers, led by George Aldrich, astronauts can breathe a little bit easier. Aldrich is the “chief sniffer” at the White Sands Test Facility in New Mexico. His’s job is to smell items before they can be flown in the space shuttle.
Aldrich explained that smells change in space and that once astronauts are up there, their stuck with whatever smells are onboard with them. In space, astronauts aren’t able to open the window for extra ventilation. He also said that its important not to introduce substances that will change the delicate balance of the climate of the International Space Station and the space shuttle.
