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:

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, https://chat.openai.com/chat.

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 Merriam-Webster.com (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 Merriam-Webster.com 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.)