她立刻认出那个声音是她多年不见的老朋友。

She immediately ___knew the voice as her long-lost friend.

你知道明天的会议几点开始吗？

Do you ___know what time tomorrow's meeting starts?

我认识这家咖啡馆的老板很多年了。

I've ___known the owner of this coffee shop for many years.

你真的了解这个问题的严重性吗？

Do you ___know how serious this problem is?

她亲身经历过战争的残酷。

She has ___known the cruelty of war firsthand.