premise: A welder is working outside by some concrete ruble
hypothesis: The worker is fixing the concrete structure by welding it back together after the accident
explanation_1: The ruble may be from a controlled explosion not from an accident.
explanation_2: Working on concrete ruble doesn't always mean there was an accident
explanation_3: Concrete structures don't necessarily have an accident.
premise_logic: exists e1 s1 s2 x1 x2.(by(e1,x2) & n_ruble(x2) & a_concrete(s2) & Theme(s2,x2) & a_outside(s1) & Manner(e1,s1) & Actor(e1,x1) & v_work(e1) & n_welder(x1))
hypothesis_logic: exists e1 e2 s1 s2 x1 x2 x3.(n_accident(x3) & n_thing(x2) & n_structure(x2) & a_concrete(s1) & Theme(s1,x2) & n_worker(x1) & by(e1,e2) & after(e2,x3) & r_back(e2) & a_together(s2) & Manner(e2,s2) & Theme(e2,x2) & Actor(e2,x1) & v_weld(e2) & Theme(e1,x2) & Actor(e1,x1) & v_fix(e1))