A man in a black and gray coat is riding a motorcycle across a bridge.
A man is on a motorcycle.
Riding a motorcycle implies the man is on the motorcycle.
exists e1 s1 s2 x1 x2 x3 x4.(across(e1,x4) & n_bridge(x4) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_motorcycle(x3) & in(x1,x2) & n_coat(x2) & a_gray(s2) & Theme(s2,x2) & a_black(s1) & Theme(s1,x2) & n_man(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_motorcycle(x2)) & n_man(x1))