New Questions and Answers

Q. In compound sentences, should the verb tenses match?

A. We first saw this question more than a month ago (past indicative), but only now are we publishing our answer (present progressive), which we hope will have reached you in time (present indicative followed by future perfect). Verb tenses can and should change as needed, even in the middle of a sentence, to describe things that occur at different times.

Q. Would Chicago weigh in on whether a comma can be used to introduce a block quotation? The second example in CMOS 13.23 suggests that this is acceptable when the quotation continues from the paragraph that introduces it. But what about situations like the following?

According to commentator Jean Smith,

Life for many in the province has been increasingly difficult for nearly a decade . . .

This question has been debated in the forums for years, so we would all love to have some light shed on the subject!

A. A block quotation makes it easier for readers to distinguish the words of a longer quotation from the surrounding text. It can also be used for shorter quotations that require special emphasis.

But aside from that, a block quotation is no different from a quotation that’s been run in to the surrounding text and identified with the help of quotation marks, like this:

According to commentator Jean Smith, “Life for many in the province has been increasingly difficult for nearly a decade . . .”

If the quotation would normally be introduced with a comma, use a comma when it’s presented as a block. The comma in your example is perfect, as is the capital L in “Life.”

Q. How do you cite images generated by DALL·E?

A. According to an article on the website of OpenAI, the organization responsible for DALL·E, “If you’d like to cite DALL·E, we’d recommend including wording such as ‘This image was created with the assistance of DALL·E 2’ or ‘This image was generated with the assistance of AI’ ” (see “How Should I Credit DALL·E in My Work?,” accessed March 7, 2023).

In other words, be sure to give credit to the source, as you would for any image (see CMOS 3.29–37). Here’s an image created by DALL·E 2:

AI-generated image of a modern office rendered as a cubist painting

The credit for that image might read as follows (with the prompt used to generate the image in quotation marks):

“A modern office rendered as a cubist painting,” image generated by OpenAI’s DALL·E 2, March 5, 2023.

While we’re on the subject of AI, the OpenAI article linked to above ends with the following statement: “This article was generated with the help of GPT-3.” GPT-3 is the third iteration of the generative language model used in the development of ChatGPT, the chatbot that was released to the public in November 2022.

Q. How do you recommend citing content developed or generated by artificial intelligence, such as ChatGPT? Many scholarly publishers are requiring its identification though also requiring human authors to take responsibility for it and will not permit the AI to have “authorship.”

A. You do need to credit ChatGPT and similar tools whenever you use the text that they generate in your own work. But for most types of writing, you can simply acknowledge the AI tool in your text (e.g., “The following recipe for pizza dough was generated by ChatGPT”).

If you need a more formal citation—for example, for a student paper or for a research article—a numbered footnote or endnote might look like this:

1. Text generated by ChatGPT, March 7, 2023, OpenAI,

ChatGPT is the author of the content, and the date is the date the text was generated. OpenAI (the organization that developed ChatGPT) is then listed as the publisher or sponsor of the content. After that, the URL tells us where the ChatGPT tool may be found, but because readers can’t get to the cited content (see below), that URL isn’t an essential element of the citation.

If the prompt hasn’t been included in the text, it can be included in the note:

1. ChatGPT, response to “Explain how to make pizza dough from common household ingredients,” March 7, 2023, OpenAI.

If you’ve edited the AI-generated text, you should say so in the text or at the end of the note (e.g., “edited for style and content”). But you don’t need to say, for example, that you’ve applied smart quotes or adjusted the font; changes like those can be imposed silently (see CMOS 13.7 and 13.8).

If you’re using author-date instead of notes, any information not in the text would be placed in a parenthetical text reference. For example, “(ChatGPT, March 7, 2023).”

But don’t cite ChatGPT in a bibliography or reference list. Though OpenAI assigns unique URLs to conversations generated from your prompts, those can’t be used by others to access the same content (they require your login credentials), making a ChatGPT conversation like an email, phone, or text conversation—or any other type of personal communication (see CMOS 14.214 and 15.53).

To sum things up, you must credit ChatGPT when you reproduce its words within your own work, but that information should be put in the text or in a note—not in a bibliography or reference list. Other AI-generated text can be cited similarly. Check back with us for updates on this evolving topic.

For some considerations on the use of AI in scholarly publishing and the responsibilities of authors, start with this position statement on authorship and AI tools from COPE (Committee on Publication Ethics).

Q. Which is correct: hooves or hoofs? I can’t find a definitive answer.

A. The most common plural form of the noun hoof in American English is hooves. In British English, it’s hoofs. You can glean this information from the entries for hoof at (which records common American usage) and in the OED (which reflects British usage).

Q. I searched in vain for guidance about the use of the word “early” in expressions like “in the early twentieth century.” What is the maximum number of years (five, ten, twenty-five) that would still make sense? Could we consider this to mean “in the first quarter of the twentieth century”?

A. The word “early” will always be an approximation. But we like your idea of using a quarter century as the cutoff point, which would allow us to define “early” as anything that happens up to about 1925, “middle” as the fifty-year period from 1925 to 1975, and “late” as anything after 1975.

Q. Is it okay to write “New York Times bestseller” even though the list is called “The New York Times Best Sellers”? The advice in CMOS 8.172 does not really cover this scenario. Thank you!

A. Yes. Unless you’re referring specifically to the title of that list (as it’s styled on the Times website), you can use the name of the publication (New York Times) attributively and treat “bestseller” as an ordinary noun (as you’ve done).

(Note that the entry at for “bestseller” was updated in 2022 to list the one-word form ahead of two-word “best seller,” an equal variant. References on this site to “best seller” predate that change.)

February Q&A

Q. Would CMOS lowercase the noun preceding the number in each below? Yes or no?

He was called to aisle 8.
The meeting was at building 50.
The accident happened on interstate 90.
Tom got off at exit 12.
Holyfield fell in round 4.
The cashier stole cash from register 7.
The incident happened at terminal 1.

Thank you.

A. Words like “interstate” and “highway” are generally considered part of the name and capitalized: Interstate 90, Highway 66. But all the other terms in your list—from “aisle 8” to “terminal 1”—would be treated as generic and lowercased.

Q. If a document references only one figure, should it be labeled “Figure 1” or assigned no number?

A. A lone figure, even if it is referred to in the text, can usually remain unnumbered:

All but one of the posters relied on a conventional list; the outlier used an infographic (see figure).

The corresponding figure caption would begin with “Figure” or “Fig.” This approach is recommended by the AMA Manual of Style (11th ed., and Scientific Style and Format (8th ed., 30.2.1)—though the word “figure” would be capitalized in direct references in both of those styles.

But assigning a number to such a figure would be appropriate in at least three scenarios: (1) the figure is the only one in a chapter in a book featuring numbered figures in other chapters; (2) the figure is the only one in an article in a journal whose house style requires assigning numbers for all figures for consistency across articles; and (3) the figure occurs in a context that also includes more than one numbered table (e.g., fig. 1 and tables 1 and 2).

CMOS, which is a general reference, allows for any of those approaches. But note that all figures, whether they will be numbered in the published version or not, should carry a working number in the manuscript (see CMOS 3.13).

Q. Working on an architecture book that uses a lot of duplex addresses—i.e., 1522-1524 Main Street. Thought it should be an en, but someone pointed out the numbers are not inclusive, as 1523 Main Street is not part of the address. Is that correct? Should it just be a hyphen? Thanks!

A. Whoever pointed out that the numbers are not inclusive has a very good point. A hyphen is the better choice than an en dash in that context.

Q. I’m doing a research project where I analyze the currency of different countries. If I want to discuss, say, the US one-dollar bill, can I cite it directly as a document produced by the Federal Reserve, or do I need to cite an image of the bill?

A. Even if you include a detailed analysis and history, currency isn’t a document in the usual sense, and it doesn’t need to be cited. But if you include an image, give the source of the image at the end of the caption.

The watermarked front of a US one-dollar bill

The caption for the above bill might read as follows (see also CMOS 3.30):

The obverse of a $1 Federal Reserve note as issued with a new design in 1963. (Watermarked image from “The Seven Denominations,” at the US Currency Education Program website.)

For guidance on reproducing images of money, see “Currency Image Use” at the website of the Bureau of Engraving and Printing (US). For European currency, the European Central Bank offers this guidance.

Q. If someone uses multiple quotes that are not interrupted by a separate source, should the citation be with the first quote or the last?

A. If the quotations occur in the same paragraph, it’s usually best to place the note reference number (or parenthetical author-date citation) after the last one. But if the same source is relied on again in a subsequent paragraph, you’ll need to cite it again even if no other cited source has intervened.

A similar approach can work for a series of quotations from different sources in the same paragraph; see CMOS 14.57 for details and an example.

Q. I’m editing a book that follows Chicago’s general rule for spelling out numbers zero through one hundred. In the construction “on a scale of 1 to 10,” would you spell out the numbers or use numerals? Thanks!

A. According to Google’s Ngram Viewer, numerals have been consistently more common in that expression in published books—but only slightly.

Would “1 to 10” be even more popular if CMOS 9.2 didn’t advise spelling out numbers one through one hundred in most contexts? Maybe.

But you can take this answer as permission to use numerals, which seem to do a better job than spelled-out numbers at suggesting the hypothetical scale in that expression.

Q. My author wants to know whether a comma is called for in constructions like the following, where a conjunction follows the dialogue tag but doesn’t introduce an independent clause: “It’s very clear,” she replied[,] and moved off to a nearby tree. I tend to think it’s needed but can’t articulate why. I also think it needs to be “she replied, and THEN moved off.” Can you help?

A. This is a common question. Normally, a comma wouldn’t be required before the conjunction in a sentence that features a compound predicate (see CMOS 6.23):

She replied and moved off to a nearby tree.

But in dialogue, a speaker tag is usually set off from a quotation by a comma; it makes sense that, by a similar logic, the speaker tag would also be set off from any action or other narration that occurs in the same sentence:

“It’s very clear,” she replied, and moved off to a nearby tree.

And that’s what we’d advise—unless your author favors a style that’s notably light on commas and asks that you leave commas like that one out. In either case, you could add then after and, as you suggest.

Or you could switch to the present participle for the action verb, in which case a comma would be required:

“It’s very clear,” she replied, moving off to a nearby tree.

If the sequence of events is important, add a word like before or while:

“It’s very clear,” she replied, before moving off to a nearby tree.

Whatever approach you use, aim for consistency across like contexts.