not once

基本解释

Not once in three months!
三个月，一次也没有！
Not once a day, but twice a day. Sometimes three.
不是一天一次，而是一天两次，甚至是三次。
Not once in my conversations with him have I heard him talk about any ethnic group in derogatory terms, or treat whites with whom he interacted with anything but courtesy and respect.
在我与他的谈话中，从来没听到过他用贬损的语言谈及其他族裔，也没看到哪一次他不是用礼貌和尊重来对待与他交往的白人。

Not once did I question this fact. My mind told me I was on Mars as your mind tells you that you are upon Earth.
But you'll see that once you get to final projects frankly, you're not gonna want to implement everything from scratch.
但是一旦你得出了最终方案，你就不会愿意利用框架去,实现任何功能了。
哈佛公开课 - 计算机科学课程节选
Once each time. Right? I only do one swap potentially, it-- though not one potentially, each time at the end of the loop I do a swap.
每次循环做一次，对么？我其实,就可能做了一次交换，也许并不是可能，每次循环的结束我都得做一次交换。
麻省理工公开课 - 计算机科学及编程导论课程节选

Perhaps problems big enough to shake the entire system are not once-a-century events, but once-a-decade events.
FORBES: Christmas, Kurtosis, Fat Tails, Black Swans And Risk Management, Pt. 2