It's unheard of. - Yeah! Unheard of.

从没听说过 - 是啊 闻所未闻。

Swarms like this aren't totally unheard of.

这样的虫群并不完全是闻所未闻的。

The practice is not unheard of within publishing groups.

这一做法在出版集团内部不是前所未闻的事。

And these kind of attacks almost are unheard of.

这种攻击几乎闻所未见。

Mass shootings are rare but not unheard of in Thailand.

大规模枪击事件在泰国很少见，但也并非闻所未闻。

At the time, cooking with vegetable oils was almost unheard of.

那时候，菜油根本就不存在。

Controversial statements from a U.S. First Lady are not unheard of.

美国第一夫人发表有争议的声明也不是前所未闻。

Remember- this happened in the year 1906, so this was completely unheard of.

你要知道——这件事发生在1906年，所以是前所未闻的。

This kind of honesty is common from children and virtually unheard of from adults.

这样直白的语言通常只有小孩子才能说出来。

The discovery of fossilized skin is not unheard of, but it is remarkably rare.

化石皮肤的发现并非闻所未闻，不过也是相当少见。