People are watching while a construction crew builds a bridge.
The bridge is under construction.
A construction crew builds a bridge implies the bridge is under construction.
exists e1 p1 x1.(exists e2 x2 x3 x4.(Theme(e2,x4) & Actor(e2,x2) & v_build(e2) & n_bridge(x4) & n_crew(x2) & of(x2,x3) & n_construction(x3)) & while(e1,p1) & Actor(e1,x1) & v_watch(e1) & n_people(x1))
exists p1 x1.(n_bridge(x1) & exists x2.(under(x1,x2) & n_construction(x2)))