Аннотация:This paper deals with asymmetries in split DPs and PPs in mono- and bi-predicative clauses in Russian. The properties of splitting XPs were experimentally investigated in three steps of comparing the acceptability: full PP movement vs. PP wh-split; PP split vs. DP split and full DP movement vs. DP wh-split. The results show that in simple clauses split DPs are compatible with the left branch extraction transformation while PPs are not and that in dependent clauses the discontinuous spellout transformation is the only way both types of XPs can undergo splitting. These conclusions help to explain the differences in subject and object DPs opacity in simple and dependent clauses found in (Polinsky et al. 2013) and (Belova 2021).