Tom: Have you seen my keys?
Ann: I think you left them on the table in the kitchen
Tom: no, I am sure they were not there
Ann: Have you checked your backpack, pockets
Tom: sure, I have
Ann: oh no, would you loose them?
Tom: i hope not, I'll ask my colleagues 
Ann: ok, let me know
Tom: I will
Tom can't find his keys, he already checked his backpack and pockets, he'll ask his colleagues.