Learn Hardcore Ukrainian: Я купив йогурт і мед у супермаркеті. - I bought yogurt and honey at the supermarket.

купив is the past tense, perfective form of купити (to buy). It means “I bought” as a completed action.
купував is the past tense, imperfective form (“I was buying” or “I used to buy”) and emphasizes an ongoing or habitual action. For a single, finished purchase you always use the perfective купив.

Why are йогурт and мед unchanged even though they’re the objects of the verb?

Both йогурт and мед are masculine, inanimate nouns ending in a consonant. In Ukrainian, inanimate masculine nouns have identical forms in the nominative and accusative singular, so no ending changes are needed.

How do I know the gender of йогурт and мед, and why does it matter?

They both end in a consonant (–т and –д), which tells you they are masculine. Gender matters because it affects agreement: here the past-tense verb купив is masculine to match a male speaker (or third-person masculine subject).

What role does і play in йогурт і мед? Can I use a different word for “and”?

і simply means “and.” You can also use та (e.g. йогурт та мед) or й before a vowel (e.g. й яблуко), but і is the most common conjunctive particle for linking nouns.

Why is there no article like “a” or “the” before йогурт or мед?

Ukrainian has no articles. Definiteness or indefiniteness is inferred from context or by adding demonstratives (цей – “this”) or quantifiers (якийсь – “some”).

Why is it у супермаркеті, and what case is супермаркеті?

The preposition у (in/at) expresses location and requires the locative (prepositional) case. супермаркеті is the locative singular of супермаркет, formed by adding -і to the stem of a masculine noun ending in a consonant.

How do I choose between в/у and на with places (e.g. supermarket, post office, station)?

Use в or у with enclosed spaces or buildings (school, supermarket, cinema). Use на with open areas or set expressions (на пошті – “at the post office,” на вокзалі – “at the station,” на ринку – “at the market”). Some usages are idiomatic, so exposure helps.

Can I change the word order? For example, say У супермаркеті я купив мед і йогурт?

Yes. Ukrainian word order is flexible. Placing у супермаркеті at the front emphasizes the location. Swapping мед and йогурт only changes the listing order, not the meaning.

What if a woman says this sentence – does купив change?

Yes. A female speaker would say Я купила йогурт і мед у супермаркеті. The ending -ла marks feminine gender in the past tense.