Eles responderam que a nova conta estará pronta amanhã de manhã.

Responderam is the 3rd person plural preterite of responder.

• responder = to answer / to reply
• responderam = they answered / they replied

The preterite is used here because it refers to a completed action in the past: they already gave that answer.

Yes. Portuguese often drops subject pronouns when the verb ending already makes the subject clear.

So both of these are possible:

• Eles responderam que...
• Responderam que...

The version with eles may be used for:

• emphasis,
• contrast,
• or clarity if the subject might otherwise be unclear.

Here que means that and introduces a subordinate clause:

• Eles responderam que... = They answered that...

It connects the reporting verb (responderam) to what was said.

This is very common in Portuguese after verbs like:

• dizer
• achar
• explicar
• responder

Estará is the simple future of estar:

• está = is
• estará = will be

So a nova conta estará pronta means the new account/bill will be ready.

Using estará shows that the readiness is expected in the future, not now.

Portuguese could also use other future-style forms depending on tone, for example:

• vai estar pronta = is going to be ready
• fica pronta = gets ready / will be ready, depending on context
• está pronta amanhã de manhã = can sometimes be used informally for a scheduled future event

But estará pronta is a straightforward, standard way to express will be ready.

It comes from the verb estar in the simple future.

Future endings are added to the full infinitive:

• estar
  • -á = estará

Full future of estar:

• eu estarei
• você/ele/ela estará
• nós estaremos
• vocês/eles/elas estarão

So estará means he/she/it will be.

Because pronta agrees with conta, which is a feminine singular noun.

Agreement in Portuguese:

• conta = feminine singular
• adjective must match → pronta

Compare:

• o documento estará pronto
• a conta estará pronta
• os documentos estarão prontos
• as contas estarão prontas

Estar pronta means to be ready. This is a very common structure in Portuguese:

• estar
  • adjective

Here, pronta describes the state of the noun:

• a conta estará pronta = the account/bill will be ready

Portuguese often uses estar with adjectives to describe temporary states, conditions, or results.

No. Conta can mean different things depending on context, such as:

• account
• bill
• tab
• check (restaurant check)
• calculation in some contexts

In this sentence, the exact meaning depends on the situation. If the meaning has already been provided to the learner, that meaning is the one intended here. Grammatically, though, the sentence works the same way no matter which sense of conta is meant.

Both are possible, but adjective position in Portuguese can slightly affect nuance.

• nova conta often means new account / another account / a replacement account
• conta nova can sound more like an account that is new

In many real contexts, the difference is small, but adjective placement in Portuguese is not always neutral.

As a general tendency:

• adjective before the noun can sound a bit more fixed, subjective, or interpretive
• adjective after the noun can sound more literal or descriptive

So a nova conta is very natural if the idea is the new account as opposed to an old one.

It means tomorrow morning.

Breakdown:

• amanhã = tomorrow
• de manhã = in the morning

Together:

• amanhã de manhã = tomorrow morning

This is a standard and very common time expression in Brazilian Portuguese.

Because de manhã is the normal adverbial expression meaning in the morning.

Common time-of-day expressions:

• de manhã = in the morning
• à tarde = in the afternoon
• à noite = at night / in the evening

So:

• amanhã de manhã = tomorrow morning
• hoje de manhã = this morning

By contrast, da manhã is often used after clock times or in noun phrases:

• às 8 da manhã = at 8 in the morning
• o jornal da manhã = the morning newspaper

So in this sentence, de manhã is the correct choice.

Because Portuguese does not always do the same kind of tense backshifting that English does.

In English, you might say:

• They answered that the new account would be ready tomorrow morning.

In Portuguese, it is very normal to keep the future:

• Eles responderam que a nova conta estará pronta amanhã de manhã.

This is especially natural when the event is still in the future from the speaker’s point of view.

You may also hear other possibilities depending on style and context, but keeping estará is completely normal.

Yes, and that is a very natural alternative.

• estará pronta = will be ready
• ficará pronta = will become ready / will end up ready / will be ready

In many contexts, both are close in meaning. The difference is mainly in perspective:

• estará pronta focuses on the future state
• ficará pronta focuses a bit more on the process/result of becoming ready

Both are common in Brazilian Portuguese.