I had no idea that she was a thief.
He has no idea how to operate these machines.
I have no idea what time it is.
Teacher 1: Have you met the new student Sally?
Teacher 2: Yes, she is a very nice girl.
Teacher 1: I kept asking her questions in class today, but she wouldn’t respond.
Teacher 2: That’s because she is hard of hearing.
Teacher 1: I had no idea she had a hearing problem.
Teacher 2: It’s not too serious. You should make her sit in the front of the class so she can hear you better.