A man and a smiling young boy in a float vest are swimming together.
The people are in a lake.
Just because they are swimming, does not mean that they are in a lake.
exists e2 e1 p1 s1 x1 x2 x3 x4 x5.(exists s2.(Theme(s2,x1) & a_together(s2)) & Topic(e2,p1) & Actor(e2,x1) & v_swim(e2) & subset_of(x3,x1) & in(x3,x4) & n_vest(x4) & of(x4,x5) & n_float(x5) & n_boy(x3) & a_young(s1) & Theme(s1,x3) & Actor(e1,x3) & v_smile(e1) & subset_of(x2,x1) & n_man(x2))
exists p1 x1.(n_people(x1) & exists x2.(in(x1,x2) & n_lake(x2)))