They should back used now Quechua .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 They)) (VP_4 (ATVP_1 (MD_0 should) (RB_1 back)) (VP_1 (ATVP_0 (VBD_2 used) (ADVP_0 (RB_0 now))) (NP_3 (NNP_1 Quechua))))) (DOT_0 .)))