Breakdown of Die zahme Katze hat sowohl einen guten Charakter als auch ein weiches Fell.
ein
a, an (eine)
die Katze
the cat
gut
good / well
haben
to have
Questions & Answers about Die zahme Katze hat sowohl einen guten Charakter als auch ein weiches Fell.
How exactly does sowohl ... als auch function here?
It translates to "both ... and". In this sentence, it connects two parallel direct objects: einen guten Charakter and ein weiches Fell. Because it is a coordinating conjunction, it doesn't mess with your verb placement, and the verb hat naturally applies to both halves of the phrase.
Why is it einen guten Charakter but ein weiches Fell?
Both phrases are the direct object of hat, which means they must be in the accusative case. Charakter is masculine, so the indefinite article and adjective take the masculine accusative endings (einen guten). Fell, however, is neuter, so its article and adjective take the neuter accusative endings (ein weiches).
Why does zahme end in -e in Die zahme Katze?
Katze is feminine and is the subject of the sentence (nominative case). Because it comes right after the definite article die, the adjective zahm takes a "weak" ending, which is simply -e for feminine nominative nouns.
Should there be a comma before als auch?
No. Just like the simple word und (and), the conjunction sowohl ... als auch connects words or phrases without a comma. You only use commas in German when separating clauses, not when simply connecting two items in a list like we are doing here.