18a listens for ursine creatures to head off(4)E?R?
21d American state seen in layout ahead(4)?T???
17d extremely clever soprano's part(4,2)?V?R??
12d like a poet with incredible aura-elite,not i!(8)?A?R?A??
20d bother old king buried in the past?(5)A?G??
thanks in advance for your help