Person in red jacket sits on their bike, in front of a blue van.
Young guy riding a bike in front of Blue van
Since a guy can be a person and they are on a bike in front of a blue van, it implies they are ridding the bike.
exists e1 s1 s2 x1 x2 x3 x4 x5.(ne_nam_person(x1) & in(e1,x4) & of(x4,x5) & n_van(x5) & a_blue(s2) & Theme(s2,x5) & n_front(x4) & on(e1,x3) & n_bike(x3) & of(x3,x2) & n_thing(x2) & Actor(e1,x1) & v_sit(e1) & in(x1,x2) & n_jacket(x2) & a_red(s1) & Theme(s1,x2))
exists e1 s1 x1 x2 x3 x4 x5 x6.(ne_nam_van(x5) & (x5 = x6) & ne_geo_blue(x6) & a_topic(x1) & in(e1,x4) & of(x4,x5) & n_front(x4) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_bike(x3) & (x1 = x2) & n_guy(x1) & a_young(s1) & Theme(s1,x1))