( ( Some ( of ( these ( radio waves ) ) ) ) ( ( occur ( at ( ( audio frequencies ) ( -LRB- ( ( about ( ( ( ( 100 Hz ) to ) 10 ) kHz ) ) -RRB- ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT Some)) (PP (IN of) (NP (DT these) (NN radio) (NNS waves)))) (VP (VBP occur) (PP (IN at) (NP (NP (JJ audio) (NNS frequencies)) (PRN (-LRB- -LRB-) (NP (QP (RB about) (CD 100) (CD Hz) (TO to) (CD 10) (CD kHz))) (-RRB- -RRB-))))) (. .)))
Some of these radio waves occur at audio frequencies (about 100 Hz to 10 kHz).
(ROOT (S (NP (NNP Am) (NN radio) (NNS waves)) (VP (VBP exist) (PRT (RP in)) (NP (DT the) (ADJP (QP (CD 540) (TO to) (CD 1600))) (NN khz) (NN frequency) (NN range))) (. .)))