Better sentence-writing in 30 minutes a day - Dianna Campbell 1995

Another use for the colon
Using colons
Punctuating sentence combinations

There is another way to use the colon, but if you still have difficulty with any of the other rules of punctuation, you should skip this brief section. This is a low priority compared with the other rules, and it will not be included in the cumulative exercises in the next unit. But for many writers, it is a valuable sentence-combining technique, so that is way we are presenting it here.

The colon can be used in this way:

Carol Tavris’s The Measure of Women has an interesting

subtitle: Why Women Are Not the Better Sex, the Inferior

Sex, or the Opposite Sex.

Mark the key parts of the clause before the colon. You see that we do have a complement—subtitle—-just as we always have a complement when we are using the colon before a list. But here we’re not setting up for a list; we’re setting up for an explanation of the word in the subject complement or direct object position. The word subtitle is explained by the words that follow the colon.

When you make this kind of a sentence, you can capitalize the first word after the colon if the explanation is a full sentence. If you use the capitalization option, be consistent within a piece of writing.