Many species remain unknown to scientists.

许多物种还不为科学家所知。

Don't share your friends' contact info with someone unknown to them before they agree.

在朋友同意之前，不要与他们不认识的人分享您朋友的联系信息。

His whereabouts are unknown to his family.

他的行踪连家人都不知道。

Exotic elementary particles as yet unknown to science.

科学界还不了解的基本异粒子。

The address is unknown to me.

地址未详。

The war situation was unknown to us.

战况不明。

Unknown to me, she'd organized a party for my birthday.

我不知道，她为我的生日组织了一个聚会。

Is it unknown to you?

对你来说是未知吗？

Where he lives is unknown to me.

按住哪里我可不知道。

Its greater part is unknown to me.

它的大部分对我是未知的。