A person is fishing at sunset.
Someone is trying to catch a fish.
person almost the same as  Someone
exists e1 x1 x2.(at(e1,x2) & n_sunset(x2) & Actor(e1,x1) & v_fish(e1) & n_person(x1))
exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_try(e1) & exists e2 x2.(Theme(e2,x2) & Actor(e2,x1) & v_catch(e2) & n_fish(x2)) & n_person(x1))