•The exact number of people carrying the virus is unknown.携带病毒的准确人数还不清楚。

•As recently as six months ago her name was almost unknown in Britain.就在六个月前，她的名字在英国还几乎无人知晓。

•Unknown to me, she'd organized a party for my birthday.她为我筹划了生日派对，我却还蒙在鼓里。

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•Racism is in some ways just a fear of the unknown.在某些意义上，种族主义只是一种对未知事物的恐惧罢了。

•For her latest film she deliberately chose a cast of unknowns.在新拍影片中，她特意挑了一批不知名的演员。

•It's the big unknowns that make insurance companies uneasy.令保险公司担心的是无法预测的重大事件。