请问and 的用法

ReggieXu

https://www.manhattanprep.com/gmat/forums/even-though-her-career-was-cut-short-t2603.html

i.e., if the sentence consists of nothing other than two independent clauses connected by "and", then you are almost certain to see a comma between those clauses -- because, in that case, the presence of the comma helps to elucidate the structure of the sentence.

on the other hand, if the structure of the sentence is actually
EVEN THOUGH (clause1 AND clause2), (clause3)
... then the lack of a comma between "clause1" and "clause2" actually renders the overall structure of the sentence much clearer.

so, in short, yes, you're right about this.