A boy in a white t-shirt does a trick with his skateboard in a skate park .
It is impossible that a boy in a blue t-shirt does a trick with his skate board on the sidewalk .
It is impossible that a boy in a blue t-shirt does a trick with his skate board on the sidewalk .
It is almost certain that a boy in a blue t-shirt does a trick with his skate board on the sidewalk .
A boy in a blue t-shirt does a trick with his skate board on the sidewalk .