A dark-haired man and a little boy use screwdrivers to work on screen door.
This is a father and son.
Not all men working with boys are father and son, the relationship between them cannot be inferred.
exists p1 s1 s2 s3 x1 x2 x3 x4.(a_topic(s1) & subset_of(x2,s1) & Topic(x2,p1) & exists e1 x5 x6.(on(e1,x5) & n_door(x5) & of(x5,x6) & n_screen(x6) & Actor(e1,x2) & v_work(e1)) & n_screwdriver(x2) & of(x2,x4) & n_use(x4) & of(x2,x3) & n_boy(x3) & a_little(s3) & Theme(s3,x2) & subset_of(x1,s1) & n_man(x1) & a_dark-haired(s2) & Theme(s2,x1))
exists p1 x1.(n_thing(x1) & exists x2 x3 x4.((x1 = x2) & n_son(x4) & n_father(x3) & subset_of(x4,x2) & subset_of(x3,x2)))