it must be the end of the world : 
(ROOT (S (NP (PRP it)) (VP (MD must) (VP (VB be) (NP (NP (DT the) (NN end)) (PP (IN of) (NP (DT the) (NN world)))))) (: :)))
(ROOT (S (NP (PRP )) (VP (MD ) (VP (VB ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (DT ) (NN )))))) (: )))