Magistra rogat uter discipulus sententiam recte transferre possit.

Uter means which of the two? It is used when the choice is between two people or things.

So uter discipulus means which student (of the two).

By contrast, quis is more general: who? or sometimes which person? without the special idea of one of two.

Uter discipulus is nominative singular masculine.

That is because it is the subject of possit in the indirect question:

• uter discipulus ... possit = which student can/may be able to...

Even though magistra is asking, the person doing the action of posse / transferre inside the subordinate clause is the student, so discipulus must be nominative.

Because uter is singular. It asks about which one of two students, not both of them together.

So Latin naturally has:

• uter discipulus = which student of the two

If the sentence were talking about several students in a different way, the wording would change.

Sententiam is the direct object of transferre.

So the structure is:

• transferre sententiam = to translate the sentence

Because transferre is a transitive verb, the thing being translated goes into the accusative case.

Because it modifies the verb transferre, not a noun.

• recte transferre = to translate correctly

An adjective would describe a noun, but here the idea is how the student translates. That requires an adverb, so Latin uses recte.

It depends on possit.

The verb possum often takes a complementary infinitive:

• possum facere = I can do
• possit transferre = he/she can translate

So transferre is the action that the student is able to do.

Because this is an indirect question after rogat.

Latin regularly uses the subjunctive in indirect questions:

• direct question: Uter discipulus sententiam recte transferre potest?
• indirect question: Magistra rogat uter discipulus sententiam recte transferre possit.

So possit is not subjunctive because of doubt in the English sense; it is subjunctive because Latin grammar requires it in this kind of clause.

The main verb rogat introduces a question that is being reported rather than asked directly.

Compare:

• Uter discipulus sententiam recte transferre potest?
  = a direct question

• Magistra rogat uter discipulus sententiam recte transferre possit.
  = the teacher asks which student can translate the sentence correctly

The second sentence reports the content of the question, so it is an indirect question.

Because the clause is not a whether-question. It is a which-question, introduced by uter itself.

Latin can introduce indirect questions with interrogative words such as:

• quis = who
• quid = what
• cur = why
• ubi = where
• uter = which of two

So uter already signals the question.

Rogat is present indicative active, third person singular from rogare.

It simply states what the teacher is doing:

• magistra rogat = the teacher asks / is asking

In a basic grammar sentence like this, the present tense is often used just to present the action plainly.

Not for this exact meaning.

The accusative + infinitive is used for an indirect statement, not an indirect question. For example:

• Magistra scit discipulum sententiam transferre posse.
  = The teacher knows that the student can translate the sentence.

But here the teacher is asking which student, so Latin uses an indirect question with uter and a subjunctive verb:

• uter discipulus ... possit

The word order is fairly flexible, but the given order is natural and clear.

Latin marks grammatical function mostly by endings, not by strict word order. So readers know:

• magistra = subject of rogat
• uter discipulus = subject of possit
• sententiam = object of transferre

The sentence is arranged in a way that lets the main clause come first and then the indirect question follow.

A useful way to divide it is:

• Magistra rogat = main clause
• uter discipulus sententiam recte transferre possit = indirect question

Inside the indirect question:

• uter discipulus = subject
• sententiam = object
• recte = adverb
• transferre = infinitive depending on possit
• possit = finite verb of the clause

So the sentence has one main verb, rogat, and then a subordinate clause whose verb is possit.