R**bull,
Did you actually check what you wrote?
"On/upon and in/into are
equally interchangeable"
followed shortly after by
"I would say I was sitting on the
sofa watching TV. Not upon. so yes some sentences you can ´t interchange"
They can ´t be equally interchangeable then, can they?
(I ´m ignoring the obviously unintentional ambiguity in the first sentence, the
eccentric punctuation everywhere and the fact that nowhere does the MWDEU state
that these words are ´interchangeable ´)
Oh, and when you log ´in ´ or ´on ´, these words can be
classified as adverbs or intransitive prepositions; in either case, there ´s no
complement.
There ´s a difference between being finicky and being conscientious -
particularly when you ´re writing on a language forum.