Puer queritur se stilum iterum perdidisse, sed soror eum sub eadem capsa invenit.

Because queror, queri, questus sum is a deponent verb.

Deponent verbs:

• have passive-looking forms
• but an active meaning

So:

• queritur is grammatically a passive-looking form
• but it means he complains, not he is complained

This is very common in Latin, and it is something English speakers often have to get used to.

Se is the reflexive pronoun. It refers back to the subject of the main clause, which is puer.

So in:

• Puer queritur se stilum iterum perdidisse

the se means:

• himself
• or, in smoother English, simply that he

Latin uses se because the subject inside the indirect statement is the same person as the subject of queritur.

So the structure is:

• Puer queritur = the boy complains
• se perdidisse = that he has lost

If it referred to some other male person, Latin would not use se.

Because Latin is using an indirect statement.

After verbs like:

• say
• think
• know
• hear
• complain

Latin often uses:

• accusative subject + infinitive

Here:

• se = the subject of the indirect statement, in the accusative
• perdidisse = the infinitive

So:

• se stilum iterum perdidisse means
• that he has lost the stylus again

English usually uses that + finite verb, but Latin often prefers this accusative-and-infinitive construction.

Perdidisse is the perfect active infinitive of perdo, perdere, perdidi, perditum.

It shows an action that happened before the action of the main verb.

So:

• queritur = he complains
• perdidisse = to have lost / that he has lost

The sequence is:

1. he lost the stylus
2. now he is complaining about it

That is why English often translates it as:

• he complains that he has lost... or
• he complains that he lost...

Because it is the direct object of perdidisse.

He lost what?

• stilum

So:

• stilus = nominative, stylus
• stilum = accusative, the stylus

Even though perdidisse is an infinitive, it can still take a direct object just like a normal finite verb.

Because eum refers back to stilum, and stilus is a masculine noun.

In Latin, pronouns agree with the grammatical gender of the noun they refer to.

So:

• stilus = masculine
• therefore eum = him/it in the masculine accusative singular

English uses it for objects, but Latin does not have one single object-pronoun form equivalent to English it. It uses masculine, feminine, or neuter forms depending on the noun:

• masculine: eum
• feminine: eam
• neuter: id

Here, eum means it, referring to the stylus.

Because soror is the subject of invenit.

The sentence has two main parts:

• Puer queritur...
• sed soror eum... invenit

In the second part, the person doing the finding is the sister, so soror must be nominative:

• soror = sister, as subject
• eum = him/it, as object

So the contrast is:

• the boy complains
• but the sister finds it

Because sub can take either:

• the ablative for location
• the accusative for motion toward/under

Here the meaning is location:

• she finds it under the same box
• not to a place under the box

So Latin uses the ablative:

• sub eadem capsa

If there were movement to a position under something, you might expect the accusative instead.

Eadem is a form of idem, eadem, idem, meaning the same.

It agrees with capsa in:

• gender: feminine
• number: singular
• case: ablative

So:

• capsa = feminine singular
• after sub here it is ablative singular
• therefore eadem is also feminine singular ablative

Together:

• sub eadem capsa = under the same box

Iterum means again, and here it modifies perdidisse.

So the idea is:

• to have lost again or more natural English:
• that he has lost the stylus again

Its position before perdidisse is normal Latin word order, but it is understood with the losing, not with the complaining or the finding.

Latin word order is more flexible than English word order because the endings show the grammatical roles.

So:

• Puer is the subject of queritur
• se is the accusative subject of the infinitive
• stilum is the object of perdidisse
• soror is the subject of invenit
• eum is the object of invenit

That said, word order still helps with emphasis and flow.

For example:

• Puer queritur puts the boy first as the topic
• sed soror creates a contrast: but the sister
• eum before sub eadem capsa invenit keeps attention on the missing object before telling where it was found

So Latin word order is not random, but it is less rigid than English.

Yes. Strictly speaking, stilus originally means a stylus, a pointed writing instrument used on wax tablets. In many beginner texts, it is often translated more loosely as pen to make the sentence feel natural in English.

So depending on context, you may see:

• stylus
• pen
• sometimes even writing tool

All are attempts to express the same Latin word in understandable English.