their best missing parents dropped up while gravel silky across .
(ROOT_0 (S_0 (ATS_3 (NP_1 (ATNP_0 (ATNP_0 (PRPDOLLAR_0 their) (JJS_0 best)) (JJ_0 missing)) (NNS_0 parents)) (VP_4 (ATVP_3 (VBD_2 dropped) (PRT_0 (RP_0 up))) (S_2 (NP_1 (IN_2 while) (NN_3 gravel)) (ADJP_0 (JJ_1 silky) (PP_1 (IN_1 across)))))) (DOT_0 .)))