A young man sits with his elbows on his legs while he reads a book.
A teenager is flipping through a book in the library.
Not all young men are teenagers and just because he is reading a book sitting doesn't mean he is in a library.
exists e1 p1 s1 x1 x2 x3.(exists e2 x4.(Theme(e2,x4) & Actor(e2,x1) & v_read(e2) & n_book(x4)) & n_male(x1) & n_male(x1) & n_male(x1) & while(e1,p1) & with(e1,x2) & on(x2,x3) & n_leg(x3) & of(x3,x1) & n_elbow(x2) & of(x2,x1) & Actor(e1,x1) & v_sit(e1) & n_man(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(n_library(x3) & through(e1,x2) & in(x2,x3) & n_book(x2) & Actor(e1,x1) & v_flip(e1) & n_teenager(x1))