An in-line skater grinding on a rail.
The skater is sleeping.
A skater cannot be grinding and sleeping at the same time.
exists e1 s1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_rail(x3) & Actor(e1,x2) & v_grind(e1) & (x1 = x2) & n_skater(x1) & a_in-line(s1) & Theme(s1,x1))
exists e1 x1.(n_skater(x1) & Actor(e1,x1) & v_sleep(e1))