Negros walk across a train track that stretches over dirt and garbage beside a row of poor shacks .
There is a very good chance that negroes walk over train track to get to the store .
It is probably not the case that negroes walk over train track to get to the store .
There is a very good chance that negroes walk over train track to get to the store .
Negroes walk over train track to get to the store .