All at once there was someone knocking on the door.

突然有人敲门。

《柯林斯英汉双解大词典》

Once there was a farmer who owned a farm near the ocean.

从前，有个农夫在海边拥有一个农场。

youdao

Once there was a small boy called Shankar who belonged to a poor family.

从前有一个叫尚卡尔的小男孩，他来自一个贫穷的家庭。

youdao

There is literally concrete evidence of their work." Tony Hawk says skateboarding was once a sport on the edge of society.

VOA: special.2009.09.11

And it's not a la-di-dah thing where--I'll tell you, once there was a student in there who had really fantastic French and I said, "Why is your French so good?"

其实也不是那么严格要求的,我给你们讲,以前有个学生法语特好,我就问他你法语怎么这么好啊

耶鲁公开课 - 1871年后的法国课程节选

Once there was a story on grade inflation that the Yale Daily News began by saying, " As Shelly Kagan So I know I've got at least the reputation of being a hard grader.

一旦有关于成绩膨胀的故事,耶鲁日间新闻会从下面这句话开始“,薛立·卡刚,这至少让我知道了,我有严厉这么个名声。

耶鲁公开课 - 死亡课程节选

As of January 2011, where once there was one Motorola, now there were two.

FORBES: The Other Motorola

"Once there was nothing they could do about it, they accepted it, " he says.

FORBES: Magazine Article

Where once there was a stigma against indebtedness, especially to excess, this has broken down over the past century.

FORBES: Who is serious about limiting taxes?