The man is skillfully surfing a violent wave in the blue ocean.
two boys play in an intertube
Surfing is on a skateboard, not an intertube.
exists e1 s1 s2 s3 x1 x2 x3.(n_ocean(x3) & a_blue(s2) & Theme(s2,x3) & n_man(x1) & a_skillfully(s3) & Manner(e1,s3) & Theme(e1,x2) & Actor(e1,x1) & v_surf(e1) & in(x2,x3) & n_wave(x2) & a_violent(s1) & Theme(s1,x2))
exists e1 x1 x2.(in(e1,x2) & n_intertube(x2) & Actor(e1,x1) & v_play(e1) & n_boy(x1) & card_eq_2(x1))