I'm aware that I might be foolish to ask this rather simple question but it's stunning me ever since I've finished reading the Goblet of Fire.
In Harry Potter and the Goblet of Fire:
Pre-context:
Once or twice, Sirius made a noise as though about to say something,
his hand still tight on Harry’s shoulder, but Dumbledore
raised his hand to stop him, and Harry was glad of this, because it
was easier to keep going now he had started. It was even a relief; he
felt almost as though something poisonous were being extracted
from him.
The next sentence:
It was costing him every bit of determination he had to
keep talking, yet he sensed that once he had finished, he would feel
better.
I'm not absolutely sure how to explain to myself why the past perfect here is correct. This is definitely a conditional but a rather strange one to me.
I somehow want to write it as:
- …yet he sensed that once he would have finished, he would feel
better.
or even…
- …yet he sensed that once he would finish, he would feel
better.
To me "once he had finished" sounds as if "he did actually finish it once in the past".
Best Answer
In reported speech, we backshift the tense of verbs.
It is called reported speech because it probably occurs most often with the verb "say*, as in my example, but it is actually used with a whole lot more verbs. There are a lot of verbs in that list: sense isn't among them, but it should be there. In this context, sense means feel, which is in the list.
We use present perfect I have XXXed to talk about something that was started in the past and is not yet completed: once I have XXXed refers to what's going to happen when it is completed in the future. In reported speech, once I have XXXed backshifts to past perfect once she had XXXed.
We use backshift with sense: your sentence uses past perfect. Both simple past and present perfect backshift to past perfect, so we need to decide which was meant:
It's not difficult to work out that the correct reverse-backshift is present perfect.