Several people holding books, looking forward singing.
the people are throwing books at professor lockhart
Holding books are keeping the books with you, throwing books are getting ride of them.
exists e1 e2 e3 p1 s1 x1 x2 x3.(for(e2,e3) & Actor(e3,x1) & v_sing(e3) & exists s2.(Theme(s2,x1) & a_forward(s2)) & Topic(e2,p1) & Actor(e2,x1) & v_look(e2) & Theme(e1,x3) & Actor(e1,x2) & v_hold(e1) & n_book(x3) & (x1 = x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists e1 x1 x2 x3 x4.(n_people(x1) & at(e1,x3) & n_lockhart(x3) & of(x3,x4) & n_professor(x4) & Theme(e1,x2) & Actor(e1,x1) & v_throw(e1) & n_book(x2))