( ( Complex machines ) ( ( ( are merely ) ( combinations ( of ( ( ( two or ) more ) ( simple machines ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Complex) (NNS machines)) (VP (VBP are) (ADVP (RB merely)) (NP (NP (NNS combinations)) (PP (IN of) (NP (QP (CD two) (CC or) (JJR more)) (JJ simple) (NNS machines))))) (. .)))
Complex machines are merely combinations of 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.