get through one's head

[get through one's head] {v. phr.} 1. To understand or believe.

Jack couldn't get it through his head that his father wouldn't lethim go to camp if his grades didn't improve.

At last Mary got itthrough her head that she had failed to pass the test.

2. To makesomeone understand or believe.

I'll get it through his head if ittakes all night.