two back calculations could make to know assigned of so appropriate afraid missing afraid classes .
(ROOT_0 (S_0 (ATS_3 (NP_1 (ATNP_0 (CD_0 two) (JJ_1 back)) (NNS_0 calculations)) (VP_4 (MD_0 could) (VP_1 (VB_0 make) (S_2 (VP_0 (TO_0 to) (VP_1 (VB_0 know) (VP_2 (VBN_0 assigned) (PP_0 (IN_1 of) (NP_2 (ATNP_0 (ADJP_0 (ATADJP_0 (RB_1 so) (JJ_0 appropriate)) (JJ_1 afraid)) (JJ_0 missing)) (NP_4 (JJ_1 afraid) (NNS_1 classes))))))))))) (DOT_0 .)))