"I have a sandwich and fruit."
Translation:Mam kanapkę i owoce.
With "mieć" (to have) you use Accusative. "Kanapka" is a feminine noun so in Accusative it becomes "kanapkę". "Owoce" is plural form of "owoc" (masculine noun). Here Accusative form is the same as Nominative form. Look at the tables of declension: https://en.wiktionary.org/wiki/kanapka https://en.wiktionary.org/wiki/owoc
I see her.
She sees me.
Polish has much more complicated case system than English. We have 7 cases.
Nominative is a "dictionary" form of word (in singular) is a case used for subject of the sentence, when the noun/pronoun is the one "active", doing a thing, when you would use "I" in a sentence. also if a sentence has "to jest" phrase in it.
Accusative is for direct object. I see her, I eat fruit. I have a sandwich
Most verbs in Polish (in positive statements) need object in accusative case. Also there are some prepositions that need nouns in accusative.
Just for the sake of clarity, the word 'fruits' mostly exist in botanical studies and even there usually means multiple kinds of fruit – 'normal' English has irregular plural 'fruit' for the word 'a fruit', so:
- „gruszka i jabłko” = 'fruit' or rarely 'fruits' but „owoce” in Polish
- „dwie gruszki” = 'fruit' = „owoce”
- „jedna gruszka” = 'a fruit' = „owoc”
Well, the problem is that English generally uses the form "fruit" as the plural form. If it was a singular fruit here, that would need to be "a fruit" rather than "fruit".
Now, "mieć" (to have) takes a direct object in Accusative. In Accusative some genders have forms identical to Nominative (the basic one), and some identical to Genitive (you haven't encountered it yet, so let's just say that they 'change').
Accusative is identical to Nominative for: masculine inanimate nouns, neuter nouns, 'not masculine-personal plural' nouns (plural words that do not describe male people).
Accusative is different (and identical to Genitive) for: masculine animate nouns, feminine nouns, 'masculine-personal plural' nouns.
"owoc" is masculine inanimate, so it would still be "owoc" in Accusative. But as here we have plural "owoce"... it's also among those that do not change their form, it's still "owoce".