A person is walking in the water with a net.
A fisherman is about to catch a fish.
You can not infer they are trying to catch a fish.
exists e1 x1 x2 x3.(n_water(x2) & with(e1,x3) & n_net(x3) & in(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_person(x1))
exists p1 s1 x1.(Topic(s1,p1) & Actor(s1,x1) & a_about(s1) & exists e1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_catch(e1) & n_fish(x2)) & n_fisherman(x1))