The conversation between human and AI assistant.
How can I determine when to use had, have, had been etc?
How about this one: "I had been waiting for the bus for 30 minutes."
That's a good example. The construction "had been waiting" is in the past perfect continuous tense. It's used to describe an action that started in the past and continued up until a specific point in the past. In this case, the specific point in the past is when the bus arrived.