(S (S (BASENP (DT The) (NN X-ray) (JJ spectral) (NN data)) (VP (VBD showed) (S (NP (BASENP (NN two) (JJ hot) (NN gas) (NNS clouds)) (PRN (COMMA ,) (ADJP (NP (QP (BASENP (NN 150) (NN million)) (CC and) (BASENP (NN 370) (NN million))) (BASENP (NN light) (NNS years))) (JJ distant)) (COMMA ,))) (VP (VP (VBG absorbing) (BASENP (DT the) (NNS X-rays))) (PP (IN from) (BASENP (NNP Mkn) (NNP 421))))))) (PERIOD .))