a man plays ping-pong while a boy watches, meanwhile girls play in the background.
The boy's parents chaperon while they all play.
man doesn't imply parents
exists e1 p1 s1 x1 x4.(n_background(x4) & exists e2 p2 x2.(exists e3 x3.(r_meanwhile(e3) & in(e3,x4) & Actor(e3,x3) & v_play(e3) & n_girl(x3)) & Topic(e2,p2) & Actor(e2,x2) & v_watch(e2) & n_boy(x2)) & while(e1,p1) & a_ping-pong(s1) & Manner(e1,s1) & Actor(e1,x1) & v_play(e1) & n_man(x1))
(x)