( ( Complex machines ) ( ( ( combine ( ( ( two or ) more ) ( simple machines ) ) ) . ) -RRB- ) )
(ROOT (S (NP (JJ Complex) (NNS machines)) (VP (VBP combine) (NP (QP (CD two) (CC or) (JJR more)) (JJ simple) (NNS machines))) (. .) (-RRB- -RRB-)))
Complex machines combine two or more simple machines.)
(ROOT (S (S (NP (DT A) (JJ complex) (NN machine)) (VP (VBZ is) (VP (VBN described) (PP (IN by))))) (: :) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN made) (PP (IN of) (NP (QP (JJR more) (IN than) (CD one)) (JJ simple) (NN machine)))))) (. .)))
A complex machine is described by: it is made of more than one simple machine.