sentence: For example, before Heung-rok Song period it had been orally narrated without any exact scripts by extemporarily inserting songs handed down orally and witty remarks into the stories taught by a master.
modified: fix grammar: For example, before Heung-rok Song period it have been orally narrating without any exact scripts by extemporarily insert songs handed down orally and witty remarks into the stories taught by a master.