be unknown

Examples (10)

• His whereabouts were quite unknown during this period.
• This drug was practically unknown in Britain.
• Gold was totally unknown to their civilization.
• These sites are largely unknown to the British public.
• The exact cause of the problem is currently unknown.
• Her early works were largely unknown outside her hometown.
• Whether he will accept the offer is unknown at this point.
• Many species in the rainforest are still unknown to scientists.
• The exact number of casualties is still unknown.
• The origin of the mysterious signal was unknown.