He knew that the west coast of India had been the site of an ancient impact of unknown age and size.

他知道印度西海岸是年代和规模未知的古代碰撞的发生地。

youdao

How parental age increases autism risks remains unknown, but several hypotheses exist.

父母年龄是如何加大孤独症风险的仍是未知数，但存在一些假设。

youdao

The age at which the second language needs to be acquired to yield the protective effect is also unknown.

在什么年龄开始学第二门语言才能够产生推迟痴呆症的效果也是未知的。

youdao

She died in eighteen eighty-six, at the age of fifty-five, completely unknown to the world.

VOA: special.2010.07.18

He knew that the west coast of India had been the site of an ancient impact of unknown age and size.

ECONOMIST: Mass extinctions

As patients age, genetic mutations or unknown environmental factors may boost the production of deformed proteins, or old brain cells simply may become less able to dispose of debris.

FORBES: Health

Three years after her death at age 74, she remains virtually unknown in her homeland.

FORBES: A dark view