( ( Be ( able ( to ( ( combine ( simple machines ) ) ( to ( make ( complex machines ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Be) (ADJP (JJ able) (S (VP (TO to) (VP (VB combine) (NP (JJ simple) (NNS machines)) (S (VP (TO to) (VP (VB make) (NP (JJ complex) (NNS machines)))))))))) (. .)))
Be able to combine simple machines to make complex 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.