(S (S (ADVP (RB Thus)) (COMMA ,) (S (BASENP (PRP it)) (VP (VP (VBD took) (NP (RB approximately) (NP (BASENP (DT a) (NN year)) (CC and) (BASENP (NN three) (NNS months))))) (SBAR (IN for) (S (BASENP (DT the) (NNP Earth)) (VP (TO to) (VP (VB produce) (NP (BASENP (DT the) (JJ ecological) (NNS resources)) (SBAR (S (BASENP (NN humanity)) (VP (VBD used) (PP (IN in) (BASENP (DT that) (NN year)))))))))))))) (PERIOD .))