אני קונה בקבוק מים בתחנה, כי חם היום.

In Modern Hebrew, the present tense usually covers both the simple present and the present continuous.

So אני קונה can mean:

• I buy
• I am buying

The exact meaning comes from context. In this sentence, it most naturally means I am buying, because it describes something happening now.

In unpointed Hebrew writing, it does not always show that clearly.

The form קונה can represent:

• masculine singular: koné
• feminine singular: koná

So אני קונה can be said by either a man or a woman. In speech, pronunciation tells you; in normal writing without vowel marks, it may stay ambiguous unless context makes it clear.

Hebrew has no indefinite article. There is no separate word for a or an.

So:

• בקבוק = a bottle or bottle
• בקבוק מים = a bottle of water / water bottle

If a noun is indefinite, Hebrew usually just leaves it bare.

בקבוק מים is a very common Hebrew structure called construct state (in Hebrew, סמיכות).

It literally looks like bottle water, but it means:

• bottle of water
• sometimes simply water bottle

This structure is very common in Hebrew:

• כוס קפה = cup of coffee
• ספר ילדים = children's book
• תחנת רכבת = train station

You can sometimes use של in Hebrew, but בקבוק מים is the more natural basic phrasing here.

Because מים is one of those Hebrew nouns that has a plural form but often refers to a mass substance, not to separate countable things.

So even though מים looks plural, it usually just means water.

This is similar to how some words in other languages have unusual number behavior. In Hebrew, you simply learn מים as the normal word for water.

The prefix ב־ usually means in, at, or inside, depending on context.

So בתחנה can mean:

• in the station
• at the station
• sometimes in a station / at a station

In this sentence, English would usually say at the station, but Hebrew uses ב־ for that location idea.

In normal unpointed Hebrew spelling, בתחנה can be ambiguous.

It can represent:

• בְּתחנה = at/in a station
• בַּתחנה = at/in the station

When Hebrew adds ב־ to התחנה, the sounds combine, and in ordinary spelling the result still looks like בתחנה.

So you usually rely on:

• context
• pronunciation
• or vowel marks, if they are written

This is a very common feature of Hebrew prepositions with the definite article.

כי means because in this sentence.

So:

• כי חם היום = because it is hot today

It introduces the reason for the action in the main clause:

• אני קונה בקבוק מים בתחנה = main idea
• כי חם היום = reason

כי is one of the most common ways to say because in Modern Hebrew.

Because Hebrew normally does not use a present-tense form of the verb to be.

So instead of saying something literally like it is hot today, Hebrew simply says:

• חם היום = hot today

This is completely normal Hebrew grammar.

The verb to be does appear in other tenses, but in the present tense it is usually omitted.

In weather expressions and other impersonal statements, Hebrew often uses the masculine singular adjective as the default form.

So:

• חם היום = it is hot today
• קר היום = it is cold today

There is no explicit subject like it in Hebrew here. The masculine singular form works as the neutral default.

Not completely. Hebrew word order is fairly flexible, though some orders sound more natural than others.

This sentence:

• אני קונה בקבוק מים בתחנה, כי חם היום.

is a very natural order:

1. subject: אני
2. verb: קונה
3. object: בקבוק מים
4. place: בתחנה
5. reason clause: כי חם היום

But some parts can move for emphasis. For example:

• היום חם instead of חם היום is also possible

The difference is usually about focus or style, not basic meaning.

It can mean either, depending on context.

Hebrew ב־ often covers both meanings that English separates into:

• in
• at

So בתחנה could be:

• physically inside the station
• more generally at the station

In this sentence, English would most naturally interpret it as at the station, unless the wider context specifically emphasizes being inside the building.

The comma separates the main statement from the reason clause:

• אני קונה בקבוק מים בתחנה
• כי חם היום

In modern Hebrew punctuation, a comma before כי is common when the sentence has two clearly separate parts and the second explains the first.

You may not always see punctuation used exactly the same way by every writer, but this comma is perfectly natural here.