it were his perch option over a group , But they warmed the heavy air by inside .
(ROOT_0 (S_0 (ATS_3 (ATS_4 (ATS_0 (S_1 (NP_0 (PRP_1 it)) (VP_5 (VBD_1 were) (NP_3 (NP_6 (ATNP_1 (PRPDOLLAR_0 his) (NN_0 perch)) (NN_1 option)) (PP_0 (IN_1 over) (NP_5 (DT_0 a) (NN_2 group)))))) (COMMA_0 ,)) (CC_0 But)) (S_1 (NP_0 (PRP_1 they)) (VP_5 (ATVP_3 (VBD_0 warmed) (NP_6 (ATNP_1 (DT_0 the) (JJ_1 heavy)) (NN_1 air))) (PP_0 (IN_1 by) (NP_2 (NN_3 inside)))))) (DOT_0 .)))