太平洋岛屿上的人们曾经用贝壳交换货物。

People on Pacific islands once exchanged shells for goods.

youdao

土著美国人曾经用这个树的叶子来编织篮子和凉鞋，吃它的嫩芽和种子。

Native Americans once wove baskets and sandals from this tree's leaves and ate its buds and seeds.

youdao

如果你曾经用“如果我是你……”这样的句子开头，这背后是有科学依据的。

If you've ever started a sentence with, "If I were you...", there's a scientific reason behind it.

youdao

It's the ottava rima in which all of the great Italian romance epics by poets -- favorite poets of Milton's like Ariosto and Tasso -- had been written.

这是弥尔顿所钟爱的所有伟大的意大利浪漫诗人,例如阿里奥斯多和塔索,曾经用过的体裁。

耶鲁公开课 - 弥尔顿课程节选

We use this pattern to emphasize a point that has possibly been expressed in the past.

我们用这个句型来强调过去曾经表达过的一种观点。

That's what课堂 - SpeakingMax英语口语达人

I once counted the number of times he used the word the letter--O--in that poem, and I quit counting.

我曾经数过他到底在诗里用了多少个"啊",最后我放弃了

耶鲁公开课 - 美国内战与重建课程节选