Friction is one force causes a ball to roll downhill .
(Friction; is; one force causes a ball to roll downhill) Context(Friction is,List([0, 11))):(one force; causes; a ball to roll downhill) Context(Friction is one force causes,List([0, 28))):(a ball; to roll; downhill)
Friction is,List([0, 11)) Friction is one force causes,List([0, 28))
Friction one force a ball
is causes to roll
one force causes a ball to roll downhill
a ball to roll downhill
downhill