( ( ( ( WFPC-2 ( ( is n't ) ( ( efficient enough ) ( to ( ( make ( the measurements ) ) ( for ( ( a ( large sample ) ) ( of ( distant galaxies ) ) ) ) ) ) ) ) ) -- ) ( it ( ( takes ( too much ) ) ( ( observing time ) ( to ( collect ( enough light ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP WFPC-2)) (VP (VBZ is) (RB n't) (ADJP (JJ efficient) (RB enough) (S (VP (TO to) (VP (VB make) (NP (DT the) (NNS measurements)) (PP (IN for) (NP (NP (DT a) (JJ large) (NN sample)) (PP (IN of) (NP (JJ distant) (NNS galaxies))))))))))) (: --) (S (NP (PRP it)) (VP (VBZ takes) (ADJP (RB too) (JJ much)) (S (VP (VBG observing) (NP (NN time)) (S (VP (TO to) (VP (VB collect) (ADJP (RB enough) (JJ light))))))))) (. .)))
WFPC-2 isn't efficient enough to make the measurements for a large sample of distant galaxies--it takes too much observing time to collect enough light.
(ROOT (S (PP (JJ Due) (TO to) (NP (NP (DT the) (NN time)) (SBAR (S (NP (PRP it)) (VP (VBZ takes) (PP (IN for) (NP (NN light))) (S (VP (TO to) (VP (VB reach) (NP (PRP us)))))))))) (, ,) (NP (NP (NNS galaxies)) (PP (IN at) (NP (NP (DT the) (NN edge)) (PP (IN of) (NP (DT the) (NN universe)))))) (VP (VBP are) (VP (VBG distant) (PP (IN in) (NP (NP (NNS terms)) (PP (IN of) (NP (NN space) (CC and) (NN time))))))) (. .)))