Punctuation Quiz #5: Colons
All but one of the following sentences demonstrate incorrect use of the colon; revise the sentences as necessary:
1. The three types of rock are: igneous, sedimentary, and metamorphic.
2. That’s the key: What to do about rust.
3. Try the following steps: Rinse, lather, and repeat.
4. Smith said: “That’s the way I look at it.”
5. For example: Compare the two images below.
Answers and Explanations
The function of a colon is to separate two phrases or clauses when the second element amplifies or illustrates the first element.
Original: The three types of rock are: igneous, sedimentary, and metamorphic.
Correct : The three types of rock are igneous, sedimentary, and metamorphic.
A colon is redundant to a verb and should never follow one.
Original: That’s the key: What to do about rust.
Correct : That’s the key: what to do about rust.
Do not capitalize the first word of a phrase or an incomplete sentence that follows a colon unless it is a proper noun. (Some style guides recommend capitalizing the first word following a colon only when the explanatory content consists of two or more sentences. However, others consider that suggestion too restrictive and advise capitalizing one or more complete explanatory sentences; I endorse this style.)
Original: Try the following steps: Rinse, lather, and repeat.
Correct : Try the following steps: Rinse, lather, and repeat.
The imperative statement following the colon is a complete thought; this sentence is correct.
Original: Smith said: “That’s the way I look at it.”
Correct : Smith said, “That’s the way I look at it.”
An attribution should be followed by a comma, not a colon. (Exception: Use a colon if the attribution is a complete thought, as in “Smith summed up his viewpoint tersely: “That’s the way I look at it.”)
Original: For example: Compare the two images below.
Correct : For example, compare the two images below.
Always use a comma, not a colon, after an introductory phrase.
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2 Responses to “Punctuation Quiz #5: Colons”
I really find it confusing to understand: do we put a comma before the “and” between the two last items of a list, like you did in the first and third sentences — that’s, after “sedimentary” and after “lather”? I always omitted it. Was I wrong all this time?
The short answer is, either way is correct, but be consistent. Here’s a previous DailyWritingTips.com post about the topic.