Teenagers are looking out the window of a bus.
Teenagers are happily looking out the window.
Looking out a window can be done with a variety of emotion not always happily.
exists e1 x1 x2 x3.(n_window(x2) & out(e1,x2) & of(x2,x3) & n_bus(x3) & Actor(e1,x1) & v_look(e1) & n_teenager(x1))
exists e1 s1 s2 x1 x2.(n_window(x2) & a_happily(s2) & Manner(e1,s2) & Time(e1,x2) & a_out(s1) & Manner(e1,s1) & Actor(e1,x1) & v_look(e1) & n_teenager(x1))