A group of hard hatted workers smile for the camera.
A group of construction workers smiling while on break.
Just because  A group of hard hatted workers smile for the camera does not mean they are on a break.
exists e1 s1 s2 x1 x2 x3.(n_camera(x3) & for(e1,x3) & Actor(e1,x1) & v_smile(e1) & of(x1,x2) & n_worker(x2) & a_hatted(s2) & Theme(s2,x2) & a_hard(s1) & Theme(s1,x2) & n_group(x1))
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & on(e1,x5) & n_break(x5) & r_while(e1) & Actor(e1,x4) & v_smile(e1) & (x1 = x4) & of(x1,x2) & n_worker(x2) & of(x2,x3) & n_construction(x3) & n_group(x1))