دیروز برق آپارتمان برای یک ساعت نبود، اما گاز خوب کار میکرد.

A natural transliteration is:

diruz barq-e âpârtemân barâye yek sâ'at nabud, ammâ gâz khub kâr mikard.

A few notes:

• دیروز = diruz
• برقِ آپارتمان is pronounced barq-e âpârtemân
• میکرد is more standardly written می‌کرد, pronounced mikard
• ساعت here is sâ'at, with a little break between the vowels

Literally, برق آپارتمان means the apartment’s electricity or the apartment power.

This is a possession-type construction in Persian. In pronunciation, there is an ezafe after برق, so you say:

barq-e âpârtemân

That -e links the two nouns. In normal writing, this ezafe is often not shown, especially after a consonant, so you just see:

برق آپارتمان

Even though it is written without the vowel, you still pronounce the link.

نبود is the past tense negative of بودن in the form بود / نبود:

• بود = was
• نبود = was not / was not there

In this sentence, برق ... نبود means the electricity was not there. Persian often expresses the absence of something this way.

So instead of using a verb like failed or went out, Persian can simply say that the electricity was not there.

برای یک ساعت means for one hour.

• برای = for
• یک ساعت = one hour

It gives the duration of the outage. Persian commonly places this kind of time expression before the verb, as in this sentence.

You may also hear simpler time expressions in colloquial Persian, but برای یک ساعت is completely clear and normal.

اما means but.

It connects the two contrasting parts:

• the electricity was out
• the gas still worked well

So it works just like English but.

A learner should also know that Persian also uses ولی for but. Both are common, though اما can sound a little more formal or written in some contexts.

No. Here گاز means gas supply or natural gas, the kind used for cooking or heating.

In context, گاز خوب کار میکرد means the gas service was working properly. It does not mean gasoline or fuel for a car.

Here خوب means well, not just good.

In Persian, adjectives are often also used adverbially, so خوب can mean:

• good
• well

So:

• گاز خوب کار میکرد = the gas was working well

English changes good to well, but Persian often keeps خوب.

می‌کرد is the imperfective past form, and here it gives the sense of an ongoing state or activity in the past.

• کار کرد = worked, did work
• کار می‌کرد = was working / used to work / worked

In this sentence, the idea is that during that time, the gas was working. So کار می‌کرد fits better than کار کرد.

In standard modern Persian orthography, it is better written as:

می‌کرد

with a half-space between می and کرد.

Many people type it without the half-space as میکرد, and you will see that a lot in informal writing. But in careful writing, می‌کرد is preferred.

Because there is no direct object here.

را marks a specific direct object, but this sentence is built around two subjects and their predicates:

• برق آپارتمان ... نبود
• گاز خوب کار میکرد

Nothing is being acted upon as a direct object, so را is not needed.

Persian does not use articles the same way English does.

There is no mandatory separate word for the, and a/an is often expressed only when needed, sometimes with یک.

So in this sentence:

• آپارتمان can mean the apartment from context
• گاز can mean the gas
• برق آپارتمان can mean the apartment’s electricity

Persian relies much more on context than English does for definiteness.

It is understandable and basically fine, but many native speakers might choose a more idiomatic way to talk about a power outage.

For example, you might also hear:

• دیروز برق آپارتمان برای یک ساعت قطع بود، اما گاز خوب کار می‌کرد.
• دیروز برق آپارتمان یک ساعت رفته بود، اما گاز خوب کار می‌کرد.

These sound a bit more idiomatic for the power was out.

Still, برق آپارتمان ... نبود is understandable and grammatically interpretable as the electricity wasn’t there.

Because the two parts describe different kinds of situations.

In the first part, Persian expresses absence:

• برق آپارتمان ... نبود = the apartment’s electricity was not there

In the second part, Persian describes functioning:

• گاز خوب کار میکرد = the gas worked well / was working well

So the first part uses بودن to express existence or presence, while the second uses کار کردن to express operation or function. That difference is very natural in Persian.