More on apostrophes
The apostrophe has three uses: to show possession, to signal a contraction or shortened form, and to form certain plurals.
To Show Possession
Most of the uses here are simple.
John's books
the manager's dictation
Florence's problems
R & D's research
If the person or thing doing the possessing is more than one--is plural--use "S'."
the boys' hats
the ladies' assertions
our managers' meeting
How the singular possessive of a word ending in an "s" or "z" sound is expressed depends on how you would say it. For instance, I refer to the house of my friend Mel Ames as "Mel Ames's house." I do so because I pronounce the possessive of Ames as "Ames-es." You might pronounce it "Ames," in which case you should write, "Mel Ames' house." Some of these are obvious, though, because the pronunciation of the possessive is standardized.
the class's duration
Marx's doctrines
the grass's color
Ulysses' journey
Jesus' parables
All I have shown you so far concern true possession. In certain time phrases, although true possession is not suggested, one uses an apostrophe. For instance, "a month's labor" means the labor of a month, not the labor possessed by a month. So watch out for an hour's duration, a day's work, or last year's figures; they all take apostrophes.
You should remember that the possessive pronouns (my, your, his, her, its, our, and their) contain no apostrophes. The word "it's" means "it is"; "its" means possessed by "it." There is no such word as "its'" (with an apostrophe after the "s").
To Signal a Contraction
Contractions may occur in business writing in informal memos or letters; they should not appear in formal reports, letters, or memos. Examples of contractions are given below.
I don't care.
We'll see you later
We'd like more data on this.
They'll be waiting for you.
He's still upset.
To Form Certain Plurals
To make a plural out of 95% of the words in English all you need do is add an "s"--no apostrophe, no space, just add the "s." However, to make a plural out of a single letter, a word used as a word (not for its meaning), a single number, or an abbreviation, use an apostrophe before the "s."
Mind your p's and q's.
...no if's, and's, and but's...
The 6's and 9's were all reversed.
My A.M.'s are better than my P.M.'s.
A good many PhD's work here.
An acronym is a word made out of the first letters of several words. For instance, Strategic Arms Limitation Talks became S.A.L.T. or SALT; Safety Razor Division became SRD; Internal Revenue Service became IRS or I.R.S. To form the plurals of acronyms, simply add an "s" unless the abbreviation or acronym has a period at its end or would otherwise be confusing with a single lower-case "s"; then use apostrophe "s."
The stock market has no more IBMs.
We will support no more L.B.O.'s.
They sent several SOS's.
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