( ( ( ( The alernative ) ( of course ) ) ( is ( ( ( a ( ( grey ( , ( polluted ( , concrete ) ) ) ) ( , world ) ) ) ( completely devoid ) ) ( of ( ( any ( living thing ) ) ( except ( ( humans and ) ( the ( few ( ( plants and ) animals ) ) ) ) ) ) ) ) ) ) ( they ( ( need ( to ( eat ( to survive ) ) ) ) . ) ) )
(ROOT (S (S (NP (NP (DT The) (NN alernative)) (PP (IN of) (NP (NN course)))) (VP (VBZ is) (NP (NP (NP (DT a) (ADJP (JJ grey) (, ,) (JJ polluted) (, ,) (JJ concrete)) (, ,) (NN world)) (ADJP (RB completely) (JJ devoid))) (PP (IN of) (NP (NP (DT any) (VBG living) (NN thing)) (PP (IN except) (NP (NP (NNS humans)) (CC and) (NP (DT the) (JJ few) (NNS plants) (CC and) (NNS animals))))))))) (NP (PRP they)) (VP (VBP need) (S (VP (TO to) (VP (VB eat) (S (VP (TO to) (VP (VB survive)))))))) (. .)))
The alernative of course is a grey, polluted, concrete, world completely devoid of any living thing except humans and the few plants and animals they need to eat to survive.
(ROOT (S (NP (DT A) (NN moose)) (VP (VBZ eats) (SBAR (S (NP (DT a) (NN plant)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (NP (DT a) (VBG living) (NN thing)) (SBAR (WHNP (WDT that)) (S (VP (VBZ depends) (PP (IN on) (NP (DT another) (VBG living) (NN thing) (S (VP (TO to) (VP (VB survive)))))))))))))))) (. .)))