Writing Analytically, 6th Edition - Rosenwasser, David & Stephen, Jill [281]
Comma Error: two commas needed around parenthetical element
Most people regardless of age like to spend money.
Correction
Most people, regardless of age, like to spend money. [comma sandwich added]
Here, commas enclose the nonrestrictive elements; you could omit this information without significantly affecting the sense. Such is not the case in the following two examples.
Comma Error: restrictive elements should not be enclosed within commas
People, who live in glass houses, should not throw stones.
Correction
People who live in glass houses should not throw stones. [commas omitted]
Comma Error: no comma setting off restrictive clause
Please return the library book, that I left on the table.
Correction
Please return the library book that I left on the table. [comma omitted]
It is incorrect to place commas around “who live in glass houses” or a comma before “that I left on the table.” Each of these is a restrictive clause, that is, it contains information that is an essential part of what it modifies. In the first sentence, for example, if “who live in glass houses” is left out, the fundamental meaning of the sentence is lost: “People should not throw stones.” The word “who” is defined by restricting it to “people” in the category of glass-house dwellers. Similarly, in the second example the “that” clause contributes an essential meaning to “book”; the sentence is referring to not just any book but to a particular one, the one “on the table.”
So, remember the general rule: if the information in a phrase or clause can be omitted—if it is nonessential and therefore nonrestrictive—it needs to be separated by commas from the rest of the sentence. Moreover, note that nonrestrictive clauses are generally introduced by the word “which,” so a “which” clause interpolated into a sentence takes a comma sandwich. (“The dinner, which I bought for $20, made me sick.”) By contrast, a restrictive clause is introduced by the word “that” and takes no commas.
Test yourself 19.10: Comma Errors
Consider the following examples as a pair. Punctuate them as necessary, and then briefly articulate how the meanings of the two sentences differ.
The book which I had read a few years ago contained a lot of outdated data.
The book that I had read a few years ago contained a lot of outdated data.
BWE 9: SPELLING/DICTION ERRORS THAT INTERFERE WITH MEANING
Misspellings are always a problem in a final draft, insofar as they undermine your authority by inviting readers to perceive you as careless (at best). If you make a habit of using the spellchecker of a word processor, you will take care of most misspellings; however, the problems a spellchecker won’t catch are the ones that can often hurt you most. These are actually diction errors—incorrect word choices in which you have confused one word with another that it closely resembles. In such cases, you have spelled the word correctly, but it’s the wrong word. Because it means something other than what you’ve intended, you end up misleading your readers. (See “Right” and “Wrong” Words: Shades of Meaning in Chapter 17.)
The best way to avoid this problem is to memorize the differences between pairs of words commonly confused with each other but that have distinct meanings. The following examples illustrate a few of the most common and serious of these errors. Most handbooks contain a glossary of usage that cites more of these sites of confusion.
Spelling/Diction Error: “It’s” versus “Its”
Although you can’t tell a book by its’ cover, its fairly easy to get the general idea from the introduction.
Correction
Although you can’t tell a book by its cover, it’s fairly easy to get the general idea from the introduction.