Сайт долго загружается, поэтому я пока пью чай.

Загружается is from загружаться and means is loading.

The ending -ся often makes a verb:

• reflexive,
• passive-like,
• or intransitive.

Here it gives the idea that the site is loading itself / is being loaded, which is the natural Russian way to say the site is loading.

Compare:

• Я загружаю сайт = I am loading the site
• Сайт загружается = The site is loading

So in this sentence, сайт is the thing undergoing the process.

In Russian, the present tense of an imperfective verb is exactly what you use for an action in progress.

So:

• Сайт загружается = The site is loading
• Я пью чай = I am drinking tea

Russian does not need a separate am/is/are + -ing form the way English does. The simple present form can express an ongoing action when the context makes that clear.

Долго means for a long time or slowly / taking a long time in this context.

So:

• Сайт долго загружается = The site is taking a long time to load

It does not mean long in a physical sense. For physical length, Russian uses words like длинный.

Here долго is an adverb describing the process of loading.

Сайт is in the nominative case because it is the subject of the sentence — the thing that is loading.

• Сайт загружается = The site is loading

If it were the object, you might see another case:

• Я открываю сайт = I am opening the site

But here the site is the grammatical subject, so nominative is correct.

Поэтому means therefore, so, or that’s why.

It connects the two ideas:

• The site is taking a long time to load
• so I’m drinking tea for now

It shows a result or consequence:

• Сайт долго загружается, поэтому я пока пью чай.

A very natural English translation is:

• The site is taking a long time to load, so I’m drinking tea for now.

There is a comma because this sentence contains two clauses:

1. Сайт долго загружается
2. поэтому я пока пью чай

Russian normally separates such clauses with a comma, especially when they are linked by a connector like поэтому.

So the comma is standard punctuation here.

Here пока means for now, meanwhile, or in the meantime.

So:

• я пока пью чай = for now, I’m drinking tea

This is different from other uses of пока:

• Пока! = Bye!
• Подожди пока = Wait for now / wait a bit
• Пока я пью чай, он читает = While I drink tea, he reads
• Подожди, пока я приду = Wait until I come

So пока is a very flexible word. In your sentence, it means in the meantime / for now.

Пью is the imperfective form, and it fits because the speaker is describing an ongoing activity.

• пью чай = I’m drinking tea
• выпью чай = I’ll drink / I’ll finish the tea

The sentence focuses on what the speaker is doing during the wait, not on completing the tea. That is why пью is natural here.

It actually is in the accusative case, but for many masculine inanimate nouns, the accusative looks the same as the nominative.

So:

• nominative: чай
• accusative: чай

Because чай is the direct object of пью (I drink tea), it is in the accusative.

Compare with another noun:

• Я вижу стол = I see a table
• стол also stays the same in the accusative because it is masculine and inanimate.

Russian has no articles like a or the.

So сайт can mean:

• a site
• the site
• website, depending on context

And чай can mean:

• tea
• the tea
• some tea

The context tells you which meaning is intended. In this sentence, English naturally uses the site because both speaker and listener presumably know which site is being discussed.

Yes, Russian word order is flexible, but changing it can shift the emphasis.

The neutral version here is:

• Сайт долго загружается, поэтому я пока пью чай.

Other possibilities:

• Сайт долго загружается, поэтому пока я пью чай.
• Поэтому я пока пью чай, сайт долго загружается. — grammatically possible, but less natural in this context
• Я пока пью чай, потому что сайт долго загружается. — also natural, but with a different structure

Russian often uses word order to highlight what is most important, but the original sentence sounds natural and straightforward.

Not directly in the same structure, because поэтому and потому что do different jobs.

• поэтому = therefore / so
• потому что = because

Your sentence says:

• The site is loading slowly, so I’m drinking tea.

With потому что, you would usually reverse the logic:

• Я пока пью чай, потому что сайт долго загружается.
• I’m drinking tea for now because the site is taking a long time to load.

So both are possible, but the sentence structure changes.

It can mean either, depending on context, but in this sentence it most naturally means it is loading slowly right now.

Why? Because the second part gives a present, temporary reaction:

• поэтому я пока пью чай = so for now I’m drinking tea

That makes the whole sentence sound like a real-time situation:

• The site is taking a long time to load, so I’m drinking tea while I wait.

Without context, Сайт долго загружается could also describe a habitual characteristic:

• This site takes a long time to load.

But here the surrounding words point to a current situation.