They just used up to seven-hour shadows .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (NP_1 (PRP_0 They)) (ADVP_0 (RB_0 just))) (VP_3 (ATVP_3 (VBD_2 used) (PRT_0 (RP_0 up))) (PP_2 (TO_0 to) (NP_3 (JJ_1 seven-hour) (NNS_0 shadows))))) (DOT_0 .)))