The man does a trick on the fourwheeler.
A boy pops a wheelie on a bicycle.
A man refers to an adult. A boy is a child.
exists e1 x1 x2 x3.(n_fourwheeler(x3) & n_man(x1) & on(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_pop(e1) & on(x2,x3) & n_bicycle(x3) & n_wheelie(x2) & n_boy(x1))