Answer:
Episodes and Stasima.
Step-by-step explanation:
Stasimon is a choral ode, especially in tragedy, divided into strophe and antistrophe; it usually alternates with the epeisodion (episode). And the episode is an incident or an event that is part of a progression or a larger sequence.
So basically, the episodes are interspersed by stasima, i.e. choral interludes explaining or commenting on the situation developing in the play.