(S (S (ADVP (RB However)) (COMMA ,) (S (ADVP (RB sometime) (PP (IN during) (BASENP (DT the) (JJ last) (QP (NN 10) (NN billion)) (NNS years)))) (S (NP (NP (BASENP (DT a) (JJ large) (NN fraction)) (PP (IN of) (BASENP (DT the) (NNS baryons)))) (PRN (COMMA ,) (VP (ADVP (RB commonly)) (VP (VP (VP (VBN referred) (PP (TO to))) (PP (IN as) (QT (DQL ``) (BASENP (JJ ordinary) (NN matter)) (DQR '')))) (S (VP (TO to) (VP (VP (VB distinguish) (BASENP (PRP them))) (PP (IN from) (NP (BASENP (JJ dark) (NN matter)) (CC and) (BASENP (JJ dark) (NN energy))))))))) (COMMA ,))) (VP (VBP have) (VP (VBN gone) (ADJP (JJ missing))))))) (PERIOD .))