Man grooms a tree while a child helps him.
Man and child tend a tree.
These two sentences describe the same event using somewhat different words, but the words man, child, and tree mean they are related.
exists e1 p1 x1 x2.(ne_nam_man(x1) & exists e2 x3.(Theme(e2,x2) & Actor(e2,x3) & v_help(e2) & n_child(x3)) & n_male(x2) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_groom(e1) & n_tree(x2))
exists e1 x1 x2 x3 x4.(Theme(e1,x4) & Actor(e1,x1) & v_tend(e1) & n_tree(x4) & n_child(x3) & n_man(x2) & subset_of(x3,x1) & subset_of(x2,x1))