Bryson's Dictionary for Writers and Editors - Bill Bryson [131]
1. Multiple possessives. This problem can be seen here: “This is a sequel to Jeremy Paul’s and Alan Gibson’s play”(Times). The question is whether both of the apostrophes are necessary, and the answer in this instance is no. Because the reference is to a single play written jointly, only the second-named man needs to be in the possessive. Thus, it should be “Jeremy Paul and Alan Gibson’s play.” If the reference were to two or more plays written separately, both names would have to carry apostrophes. The rule is that when possession is held in common, only the nearer antecedent should be possessive; when possession is separate, each antecedent must be in the possessive.
2. Plural units of measure. Many writers who would never think of omitting the apostrophes in “a fair day’s pay for a fair day’s work” often do exactly that when the unit of measure is increased. Consider “Laker gets further thirty days credit” (Times headline); “Mr. Taranto, who had nineteen years service with the company…”(New York Times). The words should appear as days’ and years’. Alternatively, we could insert an of after the time elements (“thirty days of credit,” “nineteen years of service”). One or the other is necessary.
The problem is often aggravated by the inclusion of unnecessary words, as in each of these examples: “The scheme could well be appropriate in twenty-five years time, he said” (Times); “Many diplomats are anxious to settle the job by the end of the session in two weeks time” (Observer); “The government is prepared to part with several hundred acres worth of property” (Time magazine). Each requires an apostrophe. But that need could be obviated by excluding the superfluous wordage. What is “in twenty-five years’ time” if not “in twenty-five years”? What does “several hundred acres’ worth” say that “several hundred acres” does not?
colon. The colon marks a formal introduction or indicates the start of a series. A colon should not separate a verb from its object in simple enumerations. Thus, it would be wrong to say, “The four states bordering Texas are: New Mexico, Arkansas, Oklahoma, and Louisiana.” The colon should be removed. But it would be correct to say, “Texas is bordered by four states: New Mexico, Arkansas, Oklahoma, and Louisiana.”
comma. The trend these days is to use the comma as sparingly as form and clarity allow. But there are certain instances in which it should appear but all too often does not. Equally, it has a tendency to crop up with alarming regularity in places where it has no business. It is, in short, the most abused of punctuation marks and one of the worst offenders of any kind in the English language. Essentially the comma’s use is compulsory in three situations and recommended in a fourth.
1. When the information provided is clearly parenthetical. Consider these two sentences, both of which are correctly punctuated: “Mr. Lawson, the energy secretary, was unavailable for comment” “The ambassador, who arrived in Britain two days ago, yesterday met with the prime minister.” In both sentences, the information between the commas is incidental to the main thought. You could remove it and the sentence would still make sense. In the following examples, the writer has failed to set off the parenthetical information. I have provided slashes (the proper name, incidentally, is virgules) to show where the commas should have gone: “British cars/says a survey/are more reliable than their foreign counterparts” (editorial in the Evening Standard); “Operating mainly from the presidential palace at Baabda/southeast of Beirut, Habib negotiated over a sixty-five-day period” (Time magazine); “Mary Chatillon, director of the Massachusetts General Hospital’s Reading Language Disorder Unit/maintains: ‘It would simply appear to be…’”(Time magazine). It should perhaps be noted that failure to put in a comma is particularly common after a parenthesis, as here: “Mr. James Grant, executive director of the United Nations Children’s Fund (UNICEF)/says…”(Times).
Occasionally