对…一无所知
to not understand about something
I don't think you have any concept of the pain you have caused her. 我觉得你对自己给她造成的痛苦根本就一无所知。
Nobody here has any concept of what a good diet consists of.
The people who make these laws don't have any concept of how normal people live.
People here seem to have no concept of the rules of the road.
She's just a child - she has no concept of how much things cost.
See also: concept