Past Perfect strange usages ;)

Question

1. I've read that "We can use the past perfect followed by before to show that an action was not done or was incomplete when the past simple action happened".

Example: They left before I'd spoken to them.

----Couldn't we say, "They had already left before I was able to talk to them"? If we could, what is the difference between the two, is one of the forms preferred? I don't understand this structure because we use past perfect in this part of the sentence, that deals with the activity that was second in the order, not first.

Similarly, in this example: Sadly, the author died before he'd finished the series.

He dies first, but past perfect comes later. I can learn this rule, but I just don't get it ...

2. I ___ for my exam all morning so I was really upset when I didn't do well.

The correct answer, out of two, is "revised" (or "hadn't revised" - incorrect). But why the quiz doesn't offer "had revised", wouldn't it be the best?

Answer 1

Interesting, all to do with the recounting of the timing of events that happened or might have happened. I answer your query 1.

I start with the simple They left after I had spoken to them. In this case the order of events is clear and sensible: I spoke to them; they left. When describing these events, the perfect/past perfect usage is appropriate.

If we write They left before I'd spoken to them, we keep the perfect/past perfect construction as above, but the event sequence is no longer simple. You clearly could not speak to them after they left, so the order of events is: I was unable to speak to them (for some reason - perhaps they were preoccupied); they left; I became able to speak to them. This is the same as your own Couldn't we say ... suggestion. Your speaking to them becomes merely a suppositional event. The same analysis applies to the example of the dead author.

I suggest that this construction treats following suppositional events in the same way as previous real events. Hence: "I wrote this after reading your question" but "I wrote this before I had read others' comments"