I've only played rugby the once, and I never want to play it again. 我只打过一次橄榄球，我再也不想打了。
An opportunity as good as this arises once in a lifetime. 像这样好的机会可是千载难逢呀。
Our intention is to destroy their offensive capability once and for all. 我们的目的是彻底摧毁他们的进攻能力。
When my father came home, everything felt right once more. 当父亲回到家时，一切又变好了。
I'd like to visit the campus once more before we leave. 我想在我们离开之前再去参观一下大学。
Once again, racist attacks are increasing across Europe. 种族主义攻势在整个欧洲又开始抬头。
All right, I'll lend you the money - just this once. 好吧，我把钱借给你——仅此一回。
I went sailing once, but I didn't like it. 我玩过一次帆船，不过我不喜欢。
1 in the past, but not now -- 从前，以前；曾经，一度
They can then be easily picked up with a small moistened paint-brush and transferred at once to the alcohol in the collecting tubes.
These relations are thus indicated twice: once for the human and once for the computer.
Once again, the stimulus will be sufficient to force the correct perception.
Thus, once the partitioning of the domain is done, the determination of the 'best' function is straightforward.
In this book several main themes are at once apparent.
Holmes once again effectively examines gendered language in the workplace and provides clear ties to current theoretical frameworks.
Rate of taper could be slowed once for every 3-day decrement if re-emergent symptoms were too severe for patients to go on.
Once determined that the intersected point belongs to visible surfaces, it is necessary to determine if the point detected is within the parallelepiped boundaries.
