She know one flats had to be I .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 She)) (VP_4 (VBP_0 know) (SBAR_0 (S_1 (NP_0 (CD_0 one) (NNS_0 flats)) (VP_5 (VBD_2 had) (S_2 (VP_0 (TO_0 to) (VP_1 (VB_0 be) (NP_1 (PRP_0 I)))))))))) (DOT_0 .)))