Дедушка поправляет забор возле дома.

Because дедушка is in the nominative case, which is the case normally used for the subject of the sentence.

The ending -а can be confusing, because many feminine nouns also end in -а, but дедушка is actually a masculine noun. It refers to a male person, so adjectives and past-tense verbs agree with it as masculine:

• старый дедушка
• дедушка пришёл

So in this sentence, дедушка means grandpa / grandfather and is the one doing the action.

Поправляет comes from поправлять, an imperfective verb.

In this sentence, it most naturally means something like:

• is fixing
• is repairing
• is mending
• is straightening up / adjusting

The exact English translation depends on context. With забор (fence), the most natural meaning is usually is fixing the fence or is repairing the fence.

A useful nuance: поправлять often suggests correcting, adjusting, or making something better/right, not necessarily a full major repair.

Yes, забор is in the accusative case here because it is the direct object of поправляет.

But for many masculine inanimate singular nouns, the accusative looks exactly the same as the nominative.

So:

• nominative: забор
• accusative: забор

That is why you do not see a different form.

Compare that with an animate masculine noun:

• Я вижу брата
  Here брат changes to брата in the accusative because it is animate.

Because возле requires the genitive case.

The noun дом in the genitive singular becomes дома:

• nominative: дом
• genitive: дома

So:

• возле дома = near the house / by the house

This is very common in Russian: many prepositions require a specific case, and возле takes the genitive.

Возле means:

• near
• by
• next to (depending on context)

So возле дома means near the house or by the house.

It is similar to около, which also means near and also takes the genitive:

• возле дома
• около дома

Both are common, though возле can sometimes feel a little more like right by / beside.

Yes, поправляет is 3rd person singular present tense.

It can mean either:

• Grandpa is fixing the fence near the house
  (happening right now)

or

• Grandpa fixes/is fixing the fence near the house
  (more general or habitual, depending on context)

Because the verb is imperfective, it often describes:

• an ongoing action,
• a repeated action,
• or a general process.

Without extra context, English often translates it as is fixing here.

Russian uses aspect, and here the verb is imperfective: поправлять.

The imperfective is used when the speaker focuses on:

• the process,
• the ongoing action,
• or the repeated activity,

rather than on the completed result.

Its perfective partner is поправить. For example:

• Дедушка поправляет забор.
  Grandpa is fixing the fence. / Grandpa fixes the fence.

• Дедушка поправит забор.
  Grandpa will fix the fence. / Grandpa will get the fence fixed.

So in your sentence, the action is presented as in progress or not viewed as completed.

Yes. Russian word order is much more flexible than English because the cases show the grammatical roles.

The neutral order here is:

• Дедушка поправляет забор возле дома.

But you could also say:

• Возле дома дедушка поправляет забор.
• Дедушка возле дома поправляет забор.

These versions are all grammatical, but the emphasis changes a bit.

For example:

• Возле дома дедушка поправляет забор puts more focus on the location.
• Дедушка поправляет забор возле дома sounds like a neutral, straightforward statement.

The stress is:

• дЕдушка
• поправлЯет
• забОр
• вОзле
• дОма

So the sentence is pronounced approximately like:

• DYE-dush-ka pa-prav-LYA-yet za-BOR VOZ-le DO-ma

A few helpful notes:

• Unstressed vowels are reduced in Russian, so they often do not sound like clear English vowels.
• я in поправляет gives a lya sound.
• забор has stress on the second syllable, which is important.

Because Russian has no articles.

There is no direct equivalent of English a/an or the. Russian usually relies on:

• context,
• word order,
• and sometimes extra words,

to show whether something is definite or indefinite.

So забор can mean:

• a fence
• the fence

and дома can mean:

• of a house
• of the house

In this sentence, the most natural English translation is usually the fence and the house, but Russian does not mark that with articles.

Usually дедушка means grandfather / grandpa, and very often it refers to someone’s actual grandfather.

But in some contexts, it can also be used more loosely for:

• an elderly man,
• a grandpa-like old man,
• or as a warm, familiar way of referring to an old man.

In this sentence, though, the most natural interpretation is simply Grandpa or Grandfather.