If you check up on someone, you obtain information about them, usually secretly. I'm sure he knew I was checking up on him
If you check up on something, you find out information about it. It is certainly worth checking up on your benefit entitlements The Government employs tax inspectors to check up and make sure people pay all their tax. see also check-up
Турецкий язык - Английский Язык
Определение to check up в Турецкий язык Английский Язык словарь