После работы я зайду в зоомагазин и куплю корм для кошки.

Because после requires the genitive case.

• работа = nominative
• работы = genitive singular

So:

• после работы = after work

This is a very common pattern in Russian:

• после урока = after the lesson
• после обеда = after lunch
• после дождя = after the rain

So the learner should remember: после + genitive.

Зайду is the 1st person singular future of зайти, a perfective verb.

In this sentence, зайти в зоомагазин means something like:

• to stop by the pet store
• to drop in at the pet store
• to go into the pet store briefly/on the way

The prefix за- often adds the idea of a short visit or stopping somewhere.

So я зайду в зоомагазин is not just a neutral I will go to the pet store. It often suggests:

• I’ll stop by there
• I’ll pop in there
• I’ll go in, probably briefly, for a purpose

Because this sentence describes movement toward a destination, not location.

With в:

• в + accusative = motion into / to
• в + prepositional = being in / at

So:

• я зайду в зоомагазин = I’ll go into the pet store
• я в зоомагазине = I’m in the pet store

Here, the speaker is going somewhere, so Russian uses the accusative:

• зоомагазин → accusative singular = зоомагазин
  (same form as nominative because it is inanimate)

Куплю is the perfective future of купить, and it focuses on a completed result: the person will successfully buy the food.

Russian often uses perfective future for single completed actions in the future:

• зайду = I’ll stop by
• куплю = I’ll buy

Using буду покупать would sound more like:

• I’ll be buying
• I’ll be in the process of buying
• I’ll buy habitually / repeatedly / over some period

That does not fit as naturally here. The sentence is about two simple future actions that will be completed.

In Russian, the future can be built in two different ways:

1. Perfective verb forms by themselves express future:

   • зайду
   • куплю

2. Imperfective future uses быть

   • infinitive:
   • буду читать = I will be reading / I will read

Here, both verbs are perfective, so the future is built with a single word, not with a separate word for will.

That is why:

• я зайду = I will stop by
• я куплю = I will buy

They are related, but not the same.

• пойду = I’ll go / I’ll set off
• зайду = I’ll stop by / I’ll go in

Compare:

• После работы я пойду в зоомагазин.
  After work I’ll go to the pet store.

• После работы я зайду в зоомагазин.
  After work I’ll stop by the pet store.

So зайду gives a more specific nuance: the pet store is a stop on the way or a brief visit for a purpose.

Because для also requires the genitive case.

• кошка = nominative
• кошки = genitive singular

So:

• для кошки = for the cat

This is another very important pattern:

• для мамы = for Mom
• для друга = for a friend
• для детей = for children

So in this sentence:

• корм для кошки = cat food / food for the cat

Literally, it just means for the cat.

Russian often leaves out possessive words like my when the meaning is obvious from context. So in real life, this sentence would very naturally mean:

• I’ll buy food for my cat

But grammatically, моей is not there. If the speaker wanted to say it explicitly, they could say:

• корм для моей кошки = food for my cat

So the shorter version is perfectly natural when everyone already knows whose cat is meant.

Yes. Корм is the normal word for animal feed / pet food, while еда is general food.

So:

• еда is for people in general, though it can sometimes be used broadly
• корм is the standard word for food meant for animals

That is why корм для кошки sounds natural, just like cat food in English.

Yes, Russian word order is flexible, but this order is very natural and neutral.

The sentence starts with the time expression:

• После работы = after work

Then comes the subject:

• я

Then the actions:

• зайду в зоомагазин
• и куплю корм для кошки

This order works well because it presents the information in a smooth way:

1. when
2. who
3. what will happen

Other orders are possible, for example:

• Я после работы зайду в зоомагазин и куплю корм для кошки.
• В зоомагазин я зайду после работы и куплю корм для кошки.

These may shift emphasis slightly, but the original version is the most straightforward.

Russian often omits personal pronouns when the verb ending already makes the subject clear.

So you could say:

• После работы зайду в зоомагазин и куплю корм для кошки.

That still clearly means:

• After work I’ll stop by the pet store and buy cat food.

Why include я, then?

• for clarity
• for emphasis
• because the speaker wants a slightly more explicit, complete sentence

So both versions are possible; with я is a bit more explicit, without я is also very natural in conversation.

Most naturally, it means after work in the situation being discussed, often today after work.

Russian, like English, often leaves that unstated if context makes it clear.

So depending on context, it could mean:

• after work today
• after I finish work
• after work on that particular day we’re talking about

The sentence itself does not mark today, but in normal conversation people will usually understand the intended time from context.

Yes. И means and, and in this sentence it naturally suggests a sequence:

1. зайду в зоомагазин
2. куплю корм для кошки

In real-world logic, you stop by the pet store and then buy the food there. Russian does not need a special word like then here, because the order of the verbs already makes the sequence obvious.

So the sentence means:

• I’ll stop by the pet store and buy cat food

with a natural sense of one action following the other.