its unknown
A sentence with unknown can be I am unknown by the people at school.
it is unknown that aliens exist
are unknown
Unknow isn't a word, but "unknown" is. Sentence: The world of aliens is still UNKNOWN to humans.
Many things in space are still left unknown.
The total amount of people that were there was unknown, but it was over 2000.
The unknown creature lay asleep in front of our eyes.
unknown
The Unknown - 2012 Life Sentence 1-4 was released on: USA: 2012
The cause of the explosion was unknown.An unknown assailant broke in and hurt the homeowner.
Active voice should be used when the subject of the sentence is performing the action, making the sentence clearer and more direct. Passive voice should be used when the focus is on the action itself or when the doer of the action is unknown or less important.
They were determining the unknown factor.