It was just a one-off; it won't happen again.

这事绝无仅有；不会再发生了。

《牛津词典》

We have just a one million dollars.

我们只有一百万美元。

youdao

World Health day is more than just a one-day event.

世界卫生日不仅仅是一个为期一天的活动。

youdao

"Why aren't more science talks in a bar,right? Like this is the place where you learn and you ask and you understand things most quickly, instead of a lecture where it's really just a one-way thing."

VOA: special.2010.05.14

Because we have, as you've hopefully realized, made a concerted effort over the past several years to really reach out to students on this campus who might not otherwise have considered this as a field of exploration, just a one semester course, or even ultimately a concentration or minor.

你们也认识到了，因为我们，在过去几年中作出了共同的努力,来影响这个校园的学生们,但是某些学生可能认为这并不是一个探索性的领域,而只是学期中的一个课程而已，或者只是一门主修或选修课程。

哈佛公开课 - 计算机科学课程节选

The first one was kind of, just like a meet up and like we grab lunch and then walked.

我和第一个相亲对象只是见了一次面，我们一起吃午餐，然后一起散步。

体验男女初次会面 - SpeakingMax英语口语达人

Likely this is not just a one-time, start-to-finish exercise, but an iterative process of trial and error.

FORBES: Are You Making Something Usable? Part 5 -- What to ask?

"But anybody that looks at it as just a one-week phenomenon has missed the real point, " Shuter explains.

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"The best part about the way Ebert used Twitter was that it wasn't just a one-way conversation, " Warren said.

CNN: On Twitter, Roger Ebert found a new voice