I know that English has two past tenses, when the second past (Pluperfect) is farther back in time then the other (Simple Past). Reading stories in English, I've discovered that many stories are narrated by the author in past, with present tenses used only in quotes to convey what a character utters. And if the author wants to narrate what happened before the normal point of reference, he uses Pluperfect. The author adds had before every verb (had given). After a series of such verbs, when I start to see normal verbs in the Past Simple (gave), I understand that the author has ended the digression in the double past and come back to his or her normal point in time.
The following is an example from The Giver (Lois Lowry). I have marked with [start] and [end] the passage when the author digresses in the double past.
It was almost December, and Jonas was beginning to be frightened. No. Wrong word, Jonas thought. Frightened meant that deep, sickening feeling of something terrible about to happen. Frightened was the way [start] he had felt a year ago when an unidentified aircraft had overflown the community twice.
Instantly, obediently, Jonas had dropped his bike on its side on the path behind his family’s dwelling. He had run indoors and stayed there, alone. [end]
Now, thinking about the feeling of fear as he pedalled home along the river path, he remembered that moment of palpable, stomach-sinking terror when the aircraft had streaked above.
(The last verb had streaked is not the "double past", it tells us what has just happened and has its consequences in the point of reference.)
I have two general questions and one optional (*):
1) When an author digresses in the "double past", does he or she lose the possibility to distinguish which event happened before another? I mean, when you narrate in the present tense, you have three points in time (I don't include the future), when you narrate in past, you have 2 points in time. But in the double past, there is only one that you are in. In this case does the author have to rely only on the context and time expressions such as before and after?
2) When you change narration from the present to the past tense, Present Perfect and Past Simple assume the same form (as the last verb in the quoted passage). For example if in the present I say: "He has seen the plane and now is running away. The same plane attacked their village a year ago." When I put it in the past it becomes: "He had seen the plane and now was running away. The same plane had attacked their village a year ago." As you see, different tenses have assumed the same form. My question: Do I always have to rely on context to distinguish when an event has its consequences in the point of reference, and when it doesn't?
3*) Can you point out some ideas that can enhance my comprehension of the Past Perfect Tense?
Past Participle) with a Past tense form of the auxiliary have, instead of a Present tense form (has, have), an Infinitive form (have), or a Present Participle form (having). The Perfect construction has four principal senses, which are shifted back with the frame of reference, as you point out, by the Past tense marker.