他不曾知道思念一个人的痛苦。

He never knows missing once personal agony.

youdao

有时，你还可以发现你不曾知道的自己的才能。

Sometimes you discover new, previously unknown parts of yourself.

youdao

比如，我当然不曾知道加州有9.4%的大学生进入社区学院。

For instance, I certainly didn't know this: 9.4 percent of all college students attend community college in California.

youdao

We all know that. It has never existed.

我们都知道它从不曾存在。

耶鲁公开课 - 政治哲学导论课程节选