A man is riding a bicycle through a city.
The man is riding a skateboard
A man can not ride a bicycle and skateboard at the same time.
exists e1 x1 x2 x3.(through(e1,x3) & n_city(x3) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bicycle(x2) & n_man(x1))
exists e1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_skateboard(x2))