( ( After ( ( being ( in Calcutta ) ) ( for ( a week ) ) ) ) ( , ( we ( ( were ( beginning ( to ( develop ( respiratory problems ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN After) (S (VP (VBG being) (PP (IN in) (NP (NNP Calcutta))) (PP (IN for) (NP (DT a) (NN week)))))) (, ,) (NP (PRP we)) (VP (VBD were) (VP (VBG beginning) (S (VP (TO to) (VP (VB develop) (NP (JJ respiratory) (NNS problems))))))) (. .)))
After being in Calcutta for a week, we were beginning to develop respiratory problems.
(ROOT (S (NP (NP (DT The) (NN development)) (PP (IN of) (NP (NP (DT the) (JJ respiratory) (NN system)) (PP (IN in) (NP (DT the) (NN fetus)))))) (VP (VBZ begins) (PP (IN at) (NP (QP (RB about) (CD 4)) (NNS weeks)))) (. .)))
The development of the respiratory system in the fetus begins at about 4 weeks.