A group of people sift through shelves of books.
people reading books in a library
The people could be in a book store and are not currently at a library.
exists e1 x1 x2 x3 x4.(through(e1,x3) & of(x3,x4) & n_book(x4) & n_shelf(x3) & Actor(e1,x1) & v_sift(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_library(x4) & Theme(e1,x3) & Actor(e1,x2) & v_read(e1) & n_book(x3) & (x1 = x2) & n_people(x1))