Hi Leo! What you're talking about here is actually two different concepts: Tense and Aspect. In order to make sense of all of this, we have to think of three different time periods: 1. The time when you say your sentence (we'll call it 'N' for Now) 2. The time period you are talking about (we'll call it 'TT' for Topic Time) 3. The duration of the event that the verb describes (we'll call it 'ET' for Event Time) Tense is all about the relationship between TT and N: Past (TT < N): | Bobby in Cuba | ------- N "I was in Cuba" Present (TT = N): ..............N ...| Bobby in Cuba | "I am in Cuba" Future (TT > N) N-------| Bobby in Cuba | "I will be in Cuba" Aspect is about the relationship between TT and ET: Perfective/Simple (ET is properly contained by TT) TT: Yesterday ET: Time during which I understood printed words TT: |------------------------------------| ET: .......|-----------| "Yesterday I read a book" Imperfective/Continuous (ET properly contains TT) TT: Yesterday ET: Time during which I understood printed words TT: .........|-------------| ET: |---------------------------------| "Yesterday I was reading a book" (and I haven't finished it yet) The Perfect Aspect says that ET began BEFORE TT, and you can decide if it ended by TT (Perfective) or still hadn't (Imperfective): TT: When I saw her ET: Moving through water TT: ........|-----| ET:|--------| "I had swam a mile when I saw her" TT: .....|---| ET: |----------| "I had been swimming for an hour when I saw her" (I was still treading water) I hope that helps! (If you enjoyed my explanation (perfective past!), look me up on Find a Teacher!)

I find it useful to create a timeline when thinking about verb tenses ........................Past.......................................................Present..........................................Future ------------------------------------------------------------------!------------------------------------------------------------!-------------------------------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ .............................had been swimming .................................^^^^^^^^^^^^^^^^^^^ .................................they saw her .................................^^^^^^^^^^^^^^^^^^^ .................................she was sleeping Italki does not let me use spaces, so ........is only filler, and ^^^^^^^is actual time of action Try to fill in the timeline with your other examples and see if it makes sense to you. Let me know if you have more quedtions about this.

Both past perfect and past perfect continuous tenses indicate an action that began and was completed in the past. The difference is that past perfect continuous also implies an element of duration. "It had been raining" and "It had rained" mean almost the same thing, except for a difference in emphasis: "It had been raining" = emphasis on the duration of time, it was a continuous (but ultimately finished) action "It had rained" = the rain was a single event, not a process over time

Well, Leo. The main thing to notice here is that the difference is not a very big one, as both tenses are used to speak about the same concept; the past. Some people refer to Past Perfect as the "past of the past", and if we think of it like this, then we should think about why we would use Past Simple vs Past Continuous. In your example: She had been swimming / She had swum. We could, grammatically, use both. However, there would be small change in the meaning if we choose one instead of the other. She had been swimming - I want to emphasise that the action was an ongoing (continuing!) action. She had swum - I want to emphasise that the action was completed. SO: She'd been swimming for 2 hours when her parents came to collect her - oooh, 2 hours. That IS a long time! She'd swum in the ocean before - Aaah, so swimming in the ocean is not new to her, she has experience!