Lesson: Forming plurals and the role of the apostrophe
A common mistake in English writing appears, strangely enough, when we write lists of dos and don’ts. Many people mistakenly write “do’s and don’ts” (with an apostrophe in “dos”).
The proper way is to write dos and don’ts—with no apostrophe in dos.
Apostrophes are reserved for showing possession. Take this sentence, for example: This is Sally’s cookie. Here, the apostrophe in “Sally’s” shows us that the cookie is reserved for Sally. Sally possesses the cookie.
We also use apostrophes to indicate missing letters in contractions. When we write “shouldn’t,” for example, the apostrophe indicates the missing letter “o.”
Apostrophes rarely form plurals. This is why if you have more than one “do” on your list, you have “dos,” not “do’s.” (The only time I know of when apostrophes form plurals is with lowercase letters. Example: There are five x’s.)
Another common apostrophe conundrum
Along with “dos,” another common apostrophe mistake comes when people write about years. When writing, for instance, about the ten-year period that made up the 1990s, you would not use an apostrophe before the letter “s.” The proper way to refer to a date range, whether it is the 1990s or the 1800s or any other period of time, is to do like you do with your multiple “dos.” Simply add an “s,” and forget about the apostrophe altogether.