"Jenny is eating an egg."
Translation:Дженни ест яйцо.
There are three basic patterns in the singular:
- like компьютер or like яйцо (masculine, ends in a consonant + neuter, ends in о/е/ё)
- like мама (ends in а/я, feminine — sometimes masculine or common gender)
- like тень or ночь (feminine, ends in a "soft" consonant, always a ь at the end)
The rule of thumb is, only nouns like мама have unique Accusative forms. And only in the singular.
Masculine nouns like актёр or велосипед reuse the Genitive (for animate nouns) and the Nominative (inanimate nouns) respectively. All types of nouns will follow this rule in the plural.
That leaves neuter nouns and nouns like мышь. These reuse the Nominative.
I think animacy is pretty confusing since it appears only for some nouns. Animate/Inanimate distinction matters in the following cases:
- for "typical masculine" nouns in the singular
- for all nouns in the plural