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?