A man is swimming with a little boy who is wearing a life jacket.
A dad is teaching his son to swim.
Just because it is a man and a little boy does not mean that he is his dad, and swimming with a life jacket does not imply that he is teaching his son to swim.
exists e1 e2 s1 x1 x2 x3 x4 x5.(with(e1,x2) & Theme(e2,x4) & Actor(e2,x3) & v_wear(e2) & n_jacket(x4) & of(x4,x5) & n_life(x5) & (x2 = x3) & n_boy(x2) & a_little(s1) & Theme(s1,x2) & Actor(e1,x1) & v_swim(e1) & n_man(x1))
exists e1 p1 x1 x2 x3.(Topic(e1,p1) & exists e2.(Actor(e2,x1) & v_swim(e2)) & Theme(e1,x3) & Actor(e1,x2) & v_teach(e1) & n_son(x3) & of(x3,x1) & n_male(x1) & n_dad(x2) & n_dad(x1))