There is no much point trying to find a specific meaning or translationdirect match with an English word for these adverbs.
NeNe and paspas can beare used in negative statements, either alone or combined.
FormalYou translation of elle ne va plus au lycée depuis... by "she not going more to the high school" is weird. I'd rather expect: "she hasn't gone to the high school for..."
Anyway, formal French generally uses a split negative nene + another adverb like paspas. Spoken while spoken/casual French usuallyoften drops the first nene. : elle va plus au lycée depuis...
See also:
Quelle est la différence entre « ne », « ne … pas » et « pas » ?Quelle-est-la-différence-entre-ne-ne-pas-et-pas
What is the construction used in negating with "ne pas" (but not ne..pas)?