( ( Most centers ) ( now ( ( ( ( place two ) ( to ( ( four embryos ) ( in ( ( the womb ) ( in ( the hope ) ) ) ) ) ) ) ( that ( one ( will ( ( ( burrow ( into ( the lining ) ) ) and ) ( begin ( to ( develop normally ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (JJS Most) (NNS centers)) (ADVP (RB now)) (VP (VBP place) (NP (CD two)) (PP (TO to) (NP (NP (CD four) (NNS embryos)) (PP (IN in) (NP (NP (DT the) (NN womb)) (PP (IN in) (NP (DT the) (NN hope))))))) (SBAR (IN that) (S (NP (PRP one)) (VP (MD will) (VP (VP (VB burrow) (PP (IN into) (NP (DT the) (NN lining)))) (CC and) (VP (VB begin) (S (VP (TO to) (VP (VB develop) (ADVP (RB normally))))))))))) (. .)))
Most centers now place two to four embryos in the womb in the hope that one will burrow into the lining and begin to develop normally.
(ROOT (S (NP (NP (NNS Invertebrates)) (-LRB- -LRB-) (CC and) (NP (JJR higher) (NNS animals)) (-RRB- -RRB-)) (VP (MD can) (ADVP (RB also)) (VP (VB be) (VP (VBN placed) (PP (IN in) (NP (NP (CD one)) (PP (IN of) (NP (CD two) (NNS groups))))) (PP (VBN based) (PP (IN on) (SBAR (WHADVP (WRB how)) (S (NP (PRP they)) (VP (VBP develop) (PP (IN as) (NP (NNS embryos))))))))))) (. .)))
Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos.