When I google translate the sentence I get good grades I get Ich bekomme gute Noten, which is fine since the e ending denotes an accusative plural case, as far as I can tell.

However, if I try I don't get good grades, the translation becomes Ich bekomme keine guten Noten. Why does the appearance of a keine leads to the adjective declining with n? Which grammatical rule explains this?

  • Good catch. You have to compare "Ich bekomme gute Noten" (obeys strong declension) with "...keine guten Noten" (mixed declension), explained in the accepted answer to the linked question.
    – c.p.
    May 21, 2018 at 20:09