Colon and Semicolon Use
Examples with Discussion

The following sentences represent some interesting punctuation issues. Following the example sentences, note student comments (in quotations) about the usage and some additional comments of mine (not inside quotation marks). Start watching for colons and semicolons in the materials you read. Do the authors use them logically?

1. Specifically, the software zooms in and out; crops unwanted areas; alters size; contrast and brightness; rotates and flips; undoes changes; and prints actual and maximum sizes supported by printers.

"I'm not sure why, but I really don't like the way the semicolon is used in this example. There are no internal commas in the phrases separated by the semicolon. It seems to be overkill.”
Semicolons aren't necessary to separate the elements because there are no internal commas within any of the elements. Perhaps more important thought, the semicolon between size and contrast should be a comma. Also I would probably add a comma after constrast. Then I would probably want semicolons among all the elements.

2. Slot specific; used to enable cards in a specific slot for I/O and address commands.

"I think this is wrong. It should be a colon.” I agree with the student.

3. The requests that form a triplet will always be issued in a specific order; that is a read request followed by an invalidate or update request followed by a write request.

I would use a comma instead of the semicolon. In fact, I would enclose "that is" in commas. The semicolon is actually incorrect in that it doesn't have an independent clause after it and the second half of the sentence is not part of a series needing semicolons to separate elements.

4. "Time is always limited; therefore, it is important to prioritize your values once you discover them."

I like the way the author punctuated this. But the student said: "I disagree with this use. It would be more emphatic if two separate sentences were used.”

5. A value field of one specifies that the starting position is the current print position; the left graphics margin is set to the current horizontal position.

"The semicolon functions to indicate that the value field setting and left graphics margin settings are related. From this I assume that these two conditions are always linked. If this were not so, I think the semicolon would be inappropriate. If these conditions do occur together, the semicolon is a good connector."

I agree with the student.

6. This horizontal offset is a temporary one; it is only in effect for the current row.

"This is a good use of semicolon to connect related ideas.” I agree with the student.

7. So projects Novell Executive Vice President Darrell Miller: "The network will have self-healing capabilities, anticipate you are running out of disk space, and take on a lot of roles that a human being does today."

"I think a comma would have been better to introduce a quote.” I'd like to see the front part clearly stand as an independent clause —i.e., VP Miller projects similar ideas: . . . .

8. We segment the market into three basic groups: one growing group is small businesses, the largest installed base is departments, and the third is the large corporate segment. Each one has its own set of issues.

The colon works well here —follows ICl—reader expects information on the three groups and that's what follows. But the student said: "Colons in the middle of the sentence are confusing. Two separate sentences would have been better."

9. We have started to put that on NetWare in our latest NetWare 386: We actually do all the configuration for you.

"Because colons in the middle of a sentence are confusing, a semicolon would have been better." I think it is arguable as to whether a semicolon or colon is most appropriate here. Might be a coin toss.

10. Other new features include additional file viewers for quickly seeing the contents of a file without launching its application; a compare feature for finding duplicate files, even across multiple drives; an Archive Manager to compress, view, and decompress ZIP and ARC files; and a Move command for both copying and deleting across drives.

"Agree—one or more items in the series also need commas to make the meaning clear, so semicolons are appropriate.”

I agree with the student.

11. EtherTalk users can use LocalTalk printers; TokenTalk users can access EtherTalk file servers.

"Agree—the writer wanted to include both thoughts in the same sentence to emphasize the juxtaposition."
Nice parallel contrast between the two ICls.

12. For the moment he felt a wild hope: perhaps this really was a nightmare.

This colon usage is a bit odd. The expectation associated with a "hope" seems to be violated by the idea of a "nightmare."

13. Now for every ten jobs there may be eight applicants; four are women and three are immigrants, and three are young men, only two of whom are white, and one may take drugs.

A colon would be more appropriate than the semicolon—it would set up the detailing of information about the applicants.

14. Instead, highly sophisticated user interfaces will need to be designed and developed; interfaces capable of delivering complex assistance in a quick and natural manner.

I would use a comma instead of a semicolon. This semicolon introduces a modifier that is not an independent clause.

15. A problem for curious readers is: suppose you flip Diagram G around as if in a mirror, and label the nodes of the new tree so they increase from left to right.

In this example the colon is awkward. It doesn't ready the reader for the form of the information that follow. It would read more smoothly if the first clause was a complete ICl and if the clause order were shifted so that the noun placed right before the colon is the concept that is explained after the colon (note: hard to do with this sentence because it is hard to decipher the intended meaning!).

16. The male moth is brown in color; whereas the female is white with black markings.

"Whereas" is a subordinating conjunction and its use makes the second clause dependent. Therefore, a semicolon is inappropriate.

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