A man performing a skateboard trick on a skateboard ramp.
A skateboarder performs a difficult trick that he has been trying for weeks on a ramp.
A man performing a skateboard trick is not necessarily a skateboarder who performs a difficult trick that he has been trying for weeks.
exists e1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & on(e1,x5) & n_ramp(x5) & of(x5,x6) & n_skateboard(x6) & Theme(e1,x3) & Actor(e1,x2) & v_perform(e1) & n_trick(x3) & of(x3,x4) & n_skateboard(x4) & (x1 = x2) & n_man(x1))
exists e1 e2 s1 x1 x2 x3 x4 x5.(Theme(e2,x2) & Actor(e2,x1) & v_perform(e2) & on(e1,x5) & n_ramp(x5) & for(e1,x4) & n_week(x4) & Theme(e1,x3) & Actor(e1,x1) & v_try(e1) & (x2 = x3) & n_male(x1) & n_trick(x2) & a_difficult(s1) & Theme(s1,x2) & n_skateboarder(x1))