( ( Average ( continental crust ) ) ( ( is ( ( ( about 35 ) km ) thick ) ) ; ) )
(ROOT (S (NP (JJ Average) (JJ continental) (NN crust)) (VP (VBZ is) (ADJP (NP (QP (RB about) (CD 35)) (NN km)) (JJ thick))) (: ;)))
Average continental crust is about 35 km thick;
(ROOT (S (NP (NP (NP (DT The) (NN earth) (POS 's)) (JJ continental) (NN crust)) (, ,) (PP (IN on) (NP (NN average))) (, ,)) (VP (VBZ is) (ADJP (NP (CD 35) (NNS kilometers)) (JJ thick))) (. .)))