She looked at him and felt the instant spark of the connection she had only experienced once before.

她看着他，立刻感到了那以前只经历过一次的霎那间碰撞的火花。

youdao

Always read an exam all the way through at least once before you start to answer any questions.

在开始回答任何问题之前总是把试卷从头到尾读至少一遍。

《柯林斯英汉双解大词典》

Take action at once before it's too late!

马上采取行动，否则就太晚了！

youdao

"Wouldn't you like to go meet Missus Trotter once before we leave?"

VOA: special.2010.04.24

Alright, so maybe a little underwhelming and we saw already what this program is going to do but let's just go through this process once before we start doing more interesting things and then we'll come back and at least give you a hint of what some of these syntactic details are doing.

好吧，这个程序也许太平庸了，让人印象不够深刻,我们也知道这个程序是干嘛的,在我们开始更有意思的事情之前,让我们再来讨论一下整个过程后再回来,这些语法细节到底是在做什么呢？,先给你们一点小小的提示。

哈佛公开课 - 计算机科学课程节选

Now we worked through this just a little bit once before.

那我们比以前在深入一点

耶鲁公开课 - 聆听音乐课程节选

He's 17 and he tells a translator the Americans came to raid his father's house once before.

NPR: Sectarian Killings Divide Integrated Baghdad Suburb

China has only vetoed sanctions at the Security Council once before (in defense of Zimbabwe).

FORBES: China Boosts Gas Sales to Iran, Irks U.S.

Before the Sandusky case, Mr. Paterno's job was in jeopardy once before, in 2004.

WSJ: Joe Paterno Dies At 85 From Lung Cancer Complications