Prepositions “on” 和 "upon" 有什麼分別？

If you don't know what you are on about(115x8=920) entries ,then you didn't make sense to differentiate ,to recognize,to distinguish between them.
"on" as prep reads for the special uses of on in phrasal verbs, look at the each entry for the verb yourself.
eg:-into a position:-eg:-There is a mark on the shirt.
The diagram on page one.
Put it down on the table.
Climb on to the bed.
A picture on a wall.
A ban on smoking for you.

"upon"="on" as prep:-eg:-
The decision from CEO was based upon China's considerations.
Row upon row of seats are seen in the Peoples' Hall.of Congress.
Mile upon mile of cars were found on the main road, Beijing.
The summer vacation was almost upon sc-children again.

根據跟在很多情況下都是可以替換的，但是在一些情況下，用upon會比用on來得更合適。
情況1：從前

從前，有一個美麗的公主。
從這裡，有個地方住著一個漂亮的公主。（這裡用upon更合適）

情況2 ：（某物）在（某人）上近在咫尺；就要來臨

例：聖誕節快到了，我需要買禮物。
聖誕節快來了，我需要買些禮物。
（這裡用upon也合適）

on是在上，例如on the top，upon是剛好，例upon you reach to school