The imperfect tense. If you think of verb tenses as determining just the time of an action (future, past, presesnt) you are missing something important. Tense tells also the way in which the action happens. The most common distinction is between a perfect tense and an imperfect tense. The perfect tense tells you that the action has been completed. Imperfect means that the action has not been completed, generally in the past. Let me give you an example.
Iliad line 5:
Διὸς δ’ ἐτελείετο βουλή
“And the will of God was being accomplished.”
Look at the word τελέω: it is pronounced “teleo” and means “fulfill, accomplish, execute, perform.” If you read Aristotle, you see him talk of the telos, which is the good toward which actions are directed. Here it is the verb whose subject is the word “will.” But it’s not present or simple past. It is the imperfect tense. So, it means that while everything else happens, the rage of Achilles, the heroes being thrust into Hades, the will of Zeus is not yet accomplished, but is in process of being accomplished.
So, when you read the Iliad, the whole thing is the working out of Zeus’ will. He wants it all to happen. Troy must fall, but so must the Acheans who die in front of the city. Zeus wants it all, and is continuing to want it.