premise: Several firemen stand or sit on a gray roof while working.
hypothesis: Several fireman are playing cards indoors.
explanation_1: If they stand or sit while working, they are not playing cards.
explanation_2: A roof is outdoors not indoors.  Firemen are working therefore they are not playing cards.
explanation_3: They cannot be sitting on a gray roof while working, and playing cards indoors
premise_logic: (exists e1 s1 x1.(Actor(e1,x1) & v_stand(e1) & n_fireman(x1) & a_several(s1) & Theme(s1,x1)) | exists e3 e2 s2 s3 x2 x3.(while(e2,e3) & Actor(e3,x2) & v_work(e3) & on(e2,x3) & n_roof(x3) & a_gray(s3) & Theme(s3,x3) & Actor(e2,x2) & v_sit(e2) & n_fireman(x2) & a_several(s2) & Theme(s2,x2)))
hypothesis_logic: exists e1 s1 x1 x2 x3.(Time(e1,x3) & n_indoor(x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_card(x2) & n_fireman(x1) & a_several(s1) & Theme(s1,x1))