the boy the girl and the frog

girl says 'wheres the frog?'
boy says 'what times mum coming?'
girl says 'what?'
boy says 'what times mum coming?'
girl says 'i asked where the frog is. why did you change the subject?'
boy says 'whats a frog?
girl says 'what?'
boy says 'whats a frog?'
girl says 'what times mum coming?'
boy looks dumbfounded