premise: Group sweeping away leakage while bystanders look on.
hypothesis: A group sweeps in front of bystanders.
explanation_1: They are in front of bystanders because bystanders look on.
explanation_2: "A group sweeps" is a rewording of "Group sweeping."
explanation_3: The group sweeps by because it's sweeping away leakage.
premise_logic: exists e1 p1 x1 x2.(ne_org_group(x1) & exists e2 p2 x3.(exists s1.(Theme(s1,x3) & a_on(s1)) & Topic(e2,p2) & Actor(e2,x3) & v_look(e2) & n_bystander(x3)) & while(e1,p1) & Actor(e1,x1) & v_leakage(e1) & away(x1,x2) & n_sweeping(x2))
hypothesis_logic: exists e1 x1 x2 x3.(in(e1,x2) & of(x2,x3) & n_bystander(x3) & n_front(x2) & Actor(e1,x1) & v_sweep(e1) & n_group(x1))