In the structure of "NP1 + Dui（对）+ NP2 + ?" (NP representats noun, representative of the unknown component ), NP2 are subjected to NP1 restrictions on the choice of nouns. If the sentence is correct, NP1 and NP2 must have the same animacy hierarchy, or animacy hierarchy of NP1 above animacy hierarchy of NP2. Transitive can explain the position of NP in "NP1 + Dui（对）+ NP2 + ?". In the sentence, NP2 is participant role, so semantic orientation can't direct it. Preposition "Dui（对）" is markedness of participant role. In the structure of "NP1 + Dui （对）+NP2+?", NP should be following the animacy hierarchy.