我想知道點解英文作故事要用過去式？

英文作故事書 - 情節都是發生在過去 - 當然用過去式。
但作者如把場景拉到你眼前，使你有置身其中的感覺時
，則用的都是現在式。

Why do you use past tense for English story writing ?
The past, the past time is used.
It's because of the time before the present where it is gone by in time for the past few days, weeks, years.eg:-Aesop's Fables.
Hence, during the past; in times past; for a long time=once upon a time etc.
From the past generations to the present generations, the past tense is used.
One who has a thorough mastery in a subject of English writing, at doing something in English may use a past participle,eg:-passed, taken, gone=gone were the days in the story etc.would have used the past tense also.
We cannot change the past when applying the past time because memories of the past filled our minds on reading the past tense of the story, eg:-Aesop's Fables.
Person's past life experiences, especially when these are in Aesop's fables form are very interesting if in past tense, because we know something of the story in past tense, written by the author with a past.