Two people standing on the side of a city street .
It is impossible that a pair of jugglers stand on the side of the street , juggling for donations .
It is impossible that a pair of jugglers stand on the side of the street , juggling for donations .
It is certain that a pair of jugglers stand on the side of the street , juggling for donations .
A pair of jugglers stand on the side of the street , juggling for donations .