Mój brat mógł wypłacić pieniądze z bankomatu, ale wolał wpłacić je od razu w banku.

Polish has no articles, so there is no direct equivalent of the or a/an.

In this sentence, definiteness is understood from context:

• mój brat already means my brother, so it is naturally specific
• pieniądze means money
• w banku means in/at the bank

Polish usually lets context do the work that articles do in English.

Mój means my, and it must agree with the noun it describes.

Here:

• brat is masculine singular
• it is in the nominative case because it is the subject of the sentence

So the correct form is mój.

Compare:

• mój brat = my brother
• moja siostra = my sister
• moje dziecko = my child

Mógł is the past tense of móc, meaning can / be able to.

Here it means something like:

• could
• was able to
• had the option to

The form mógł is used because the subject is:

• masculine
• singular
• in the past

Compare:

• on mógł = he could
• ona mogła = she could
• oni mogli = they could

Also, mógł wypłacić does not mean he actually withdrew the money. It means he could have done it, but he chose something else.

After verbs like móc and woleć, Polish normally uses the infinitive, just as English uses can + verb or prefer to + verb.

So:

• mógł wypłacić = could withdraw
• wolał wpłacić = preferred to deposit

There is no extra word equivalent to English to before the infinitive in this structure.

They are opposite actions:

• wypłacić = to withdraw money
• wpłacić = to pay in / deposit money

The prefixes help show the difference:

• wy- often suggests movement out
• w- often suggests movement in

So:

• wypłacić pieniądze z bankomatu = withdraw money from an ATM
• wpłacić pieniądze w banku = deposit money at the bank

Both verbs are perfective, which means they present the action as a complete, single event.

That fits this sentence well, because it is talking about:

• one possible withdrawal
• one preferred deposit

If the sentence were about repeated or ongoing actions, Polish would more likely use imperfective forms:

• wypłacać
• wpłacać

So the perfective forms help give the sense of one completed transaction.

In Polish, pieniądze is a plural noun. It is treated grammatically as plural, even though in English money is usually singular and uncountable.

So you get forms like:

• te pieniądze = this money / these funds
• mam pieniądze = I have money

In this sentence, pieniądze is the direct object, in the accusative plural. For this noun, the accusative form is the same as the nominative:

• nominative: pieniądze
• accusative: pieniądze

Je means them, and it refers back to pieniądze.

So:

• wpłacić je = deposit them

Polish often uses a pronoun instead of repeating the noun, just like English does.

Here je is the appropriate accusative plural pronoun for a non-masculine-personal noun like pieniądze.

Because the preposition z here means from / out of, and with that meaning it takes the genitive case.

So:

• bankomat = ATM
• z bankomatu = from the ATM

That is why the ending changes from -at to -atu.

This is a very common pattern:

• z domu = from the house
• z banku = from the bank
• z bankomatu = from the ATM

Because w banku describes the location of the action: he wanted to deposit the money in / at the bank.

• w banku = in the bank / at the bank
• do banku = to the bank

So:

• idę do banku = I am going to the bank
• jestem w banku = I am in the bank
• wpłacić w banku = to deposit at the bank

Here the sentence is about where the deposit would happen, not about movement toward the bank.

Od razu means:

• right away
• immediately
• straight away

It is a very common fixed expression in Polish.

In this sentence, it shows that he preferred to deposit the money without waiting:

• wpłacić je od razu = deposit it right away

In Polish, ale normally has a comma before it when it joins two clauses.

So:

• ..., ale ... = ..., but ...

This is standard Polish punctuation.

Not completely. Polish word order is more flexible than English because case endings and verb forms already show grammatical relationships.

The given sentence is natural and neutral:

• Mój brat mógł wypłacić pieniądze z bankomatu, ale wolał wpłacić je od razu w banku.

You can move some parts around, especially je or od razu, but the emphasis changes:

• ale wolał je wpłacić od razu w banku
• ale wolał od razu wpłacić je w banku

These are possible, but the original version sounds very straightforward and natural.