Auditores, qui primo tacebant, postea rogaverunt utrum altera lectio postero die futura esset.

It has three parts:

1. Main clause: Auditores ... rogaverunt
   = The listeners asked

2. Relative clause describing auditores: qui primo tacebant
   = who at first were silent

3. Indirect question after rogaverunt: utrum altera lectio postero die futura esset
   = whether the other/second lesson would be on the following day

So the sentence is built like this:

The listeners, who at first were silent, later asked whether ...

Because auditores is the subject of the main verb rogaverunt.

• auditor = listener, hearer
• auditores = listeners

It is nominative plural masculine, meaning the listeners are the ones doing the action of asking.

Qui is a relative pronoun meaning who. It refers back to auditores.

Because auditores is:

• plural
• masculine
• nominative

the relative pronoun also appears as qui.

So:

• auditores = the listeners
• qui primo tacebant = who at first were silent

The relative pronoun must agree with its antecedent (auditores) in gender and number. Its case depends on its role inside the relative clause. Here it is the subject of tacebant, so it is nominative.

Tacebant is imperfect, meaning they were being silent, they kept silent, or more naturally in English, they were silent.

The imperfect is used here because it describes a background or ongoing situation in the past:

• first, they were silent
• later, they asked a question

So the contrast is:

• primo tacebant = at first they were silent
• postea rogaverunt = later they asked

If Latin used the perfect tacuerunt, it would sound more like a completed action: they were silent / kept silent as a single whole event. The imperfect fits better for the ongoing background state.

They are adverbs marking the sequence of events.

• primo = at first, initially
• postea = afterwards, later

They help organize the sentence in time:

• qui primo tacebant = who at first were silent
• postea rogaverunt = later they asked

So Latin is clearly contrasting initial silence with later speaking.

Rogaverunt is the perfect active indicative of rogare.

Here it means they asked.

The perfect is used because the asking is treated as a completed past action. It moves the story forward:

• they were silent at first
• then they asked

This is a very common contrast in Latin narrative:

• imperfect for background or ongoing action
• perfect for the main event

So tacebant sets the scene, and rogaverunt tells the main action.

Utrum introduces an indirect yes/no question. Here it means whether.

So:

• rogaverunt utrum ... esset
• they asked whether ... was/would be ...

This is different from an indirect question that asks for specific information, like where, why, or when.

A yes/no indirect question in Latin is often introduced by:

• utrum
• sometimes -ne
• sometimes num depending on nuance

Here utrum is a straightforward way to say whether.

Because it is inside an indirect question.

In Latin, indirect questions normally take the subjunctive, not the indicative.

So after rogaverunt (they asked), Latin uses:

• utrum ... esset

rather than an indicative form like est or erit.

This is a standard rule:

• Direct question: Eritne altera lectio postero die?
  = Will the other/second lesson be on the following day?

• Indirect question: rogaverunt utrum altera lectio postero die futura esset
  = they asked whether the other/second lesson would be on the following day

So the subjunctive here is not optional; it is the expected mood in an indirect question.

Futura esset is a way of expressing future time inside a subordinate clause with the subjunctive.

It is made from:

• futura = future participle of esse, agreeing with lectio
• esset = imperfect subjunctive of sum

Together, futura esset means something like:

• would be going to be
• more naturally: would be

Why does Latin do this? Because the lesson is in the future relative to the time when the listeners asked.

So the sense is:

• they asked whether the lesson would be on the next day

Also notice agreement:

• lectio is feminine singular
• therefore the future participle is futura, also feminine singular

Postero die is ablative singular, and it expresses time when.

• posterus, -a, -um = following, next
• dies = day
• postero die = on the following day, the next day

Latin often uses the ablative without a preposition for time when:

• eo die = on that day
• tertio die = on the third day
• postero die = on the following day

So postero die tells us when the lesson would take place.

Altera can mean:

• the other of two
• the second of two
• sometimes more loosely another

So altera lectio could mean:

• the second lesson
• the other lesson
• possibly another lesson, depending on context

Grammatically:

• altera is feminine singular nominative
• lectio is feminine singular nominative

They match because altera modifies lectio.

Since the meaning has already been given to the learner, the important grammatical point is that altera agrees with lectio in gender, number, and case.

Latin word order is more flexible because grammatical endings show how words relate to each other.

In this sentence:

• Auditores comes first for topic/emphasis
• qui primo tacebant is inserted right after it to describe the listeners
• rogaverunt comes later, after that description
• utrum ... futura esset comes at the end as the content of what they asked

A very literal order would be:

The listeners, who at first were silent, later asked whether the other lesson on the following day would be.

That sounds strange in English, but it is normal in Latin.

Latin often places the verb later and keeps related ideas grouped together by meaning rather than by a fixed English-style word order.