premise: A group of girls ride an ATV.
hypothesis: Girls ride ATV's without their helmets.
explanation_1: We don't know if the girls are with or without helmets from the first sentence.
explanation_2: Just because a group of girls ride an ATV, doesn't mean the girls ride without their helmets.
explanation_3: Girls may ride with or without helmets so it does not necessarily follow that they are riding without their helmets.
premise_logic: exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & ne_nam_atv(x3) & of(x1,x2) & n_girl(x2) & n_group(x1))
hypothesis_logic: exists e1 x1 x2 x3 x4.(-with(e1,x4) & n_helmet(x4) & of(x4,x1) & n_thing(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_'s(x2) & (x2 = x3) & ne_org_atv(x3) & n_girl(x1))
premise_sim: exists e1 x1 x2 x3.(v_ride(e1) & of(x1,x2) & ne_nam_atv(x3) & n_group(x1) & n_girl(x2) & Theme(e1,x3) & Actor(e1,x1))
hypothesis_sim: exists e1 x1 x2 x3 x4.(v_ride(e1) & of(x4,x1) & ne_org_atv(x3) & n_thing(x1) & n_helmet(x4) & n_girl(x1) & n_'s(x2) & Theme(e1,x2) & Actor(e1,x1) & -with(e1,x4) & (x2 = x3))