( ( The ( formal ( rush period ) ) ) ( ( lasts ( ( ( approximately ( a week ) ) and ) ( a half ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ formal) (NN rush) (NN period)) (VP (VBZ lasts) (NP (NP (RB approximately) (DT a) (NN week)) (CC and) (NP (DT a) (NN half)))) (. .)))
The formal rush period lasts approximately a week and a half.
(ROOT (S (NP (DT The) (JJ fetal) (NN period)) (VP (VBZ lasts) (NP (NP (QP (RB approximately) (CD 30)) (NNS weeks)) (NP (NNS weeks)))) (. .)))