( ( ( ( Approximately ( ( 30 to ) 40 ) ) hours ) ( a week ) ) . )
(ROOT (FRAG (NP (NP (QP (RB Approximately) (CD 30) (TO to) (CD 40)) (NNS hours)) (NP (DT a) (NN week))) (. .)))
Approximately 30 to 40 hours a week.
(ROOT (S (NP (DT The) (JJ fetal) (NN period)) (VP (VBZ lasts) (NP (NP (QP (RB approximately) (CD 30)) (NNS weeks)) (NP (NNS weeks)))) (. .)))