Hamish walks Bobo the dog every morning, except on Wednesdays and Fridays.
Sandy walks Bobo whenever she visits the supermarket or the fruit store. The supermarket is open every day, but the fruit store is closed on Wednesdays.
Bobo is never walked by Hamish and Sandy at the same time, but he is walked every day by exactly one of them.

That afternoon, Celine arrives at the park and sees Sandy walking Bobo. Sandy greets Celine and hands her an apple she bought from the fruit store earlier today.