Postquam stillae desierunt cadere, puella rimam parvam in tecto videt.

Postquam means after or after the time when, and it introduces a clause about something that happened earlier than the main action.

Here the earlier action is stillae desierunt cadere = the drops stopped falling. Latin very commonly uses a finite verb after postquam, and a perfect tense is especially common when the action is completed before the next event.

So the structure is:

• postquam
  • completed action
• main clause = what happens next

That is why desierunt fits well here.

Desierunt is:

• 3rd person plural
• perfect active indicative
• from desino, desinere = to stop, to cease

It agrees with stillae, which is plural, so desierunt means they stopped.

Because desino often takes an infinitive to say stop doing something.

So:

• desierunt = they stopped
• cadere = to fall

Together: desierunt cadere = they stopped falling

This is similar to English stop + -ing, but Latin usually uses desino + infinitive.

Stillae is the subject of desierunt.

Since desierunt is 3rd person plural, the subject must also be plural. The nominative plural of stilla is stillae.

So:

• stilla = one drop
• stillae = drops

In this sentence, the drops are the ones doing the action of stopping.

Because puella is the subject of the main verb videt.

The sentence has two clauses:

• Postquam stillae desierunt cadere = subordinate clause
• puella rimam parvam in tecto videt = main clause

In the main clause, puella is the one who sees, so it must be nominative singular.

Because rimam parvam is the direct object of videt.

The verb video takes a direct object in the accusative case. So both the noun and its adjective must be accusative singular feminine:

• rima → rimam
• parva → parvam

The adjective must agree with the noun in:

• gender
• number
• case

So rimam parvam means a small crack as the object of sees.

Latin word order is much more flexible than English word order. An adjective can come before or after its noun.

So both of these are grammatically possible:

• parvam rimam
• rimam parvam

The choice often depends on style, emphasis, or rhythm rather than strict grammatical necessity. In this sentence, rimam parvam is perfectly normal.

Because in with the ablative usually means in or on in a location, while in with the accusative usually means motion into or onto something.

Here the crack is located in/on the roof, not moving into it, so Latin uses the ablative:

• in tecto = in/on the roof

If there were motion toward the roof, you might expect in tectum instead.

Tecto is ablative singular of tectum.

It is ablative because it follows in in a location sense:

• in tecto = in/on the roof

So this is a standard example of in + ablative for place where something is.

Because Classical Latin has no articles like English the and a/an.

So words such as:

• puella
• rima
• tectum

can mean the girl, a girl, the crack, a crack, and so on, depending on context.

That means readers understand definiteness from the situation, not from a separate article word.

This is very common in Latin narrative. The main verb can appear in the present tense as a historical present, which makes the scene feel more vivid.

So:

• desierunt = a completed earlier action
• videt = a vivid narrative present, she sees

Latin often mixes these in storytelling:

• first, one event is completed
• then the next event is told vividly in the present

So the tense difference is not strange; it is good narrative Latin.

Videt is:

• 3rd person singular
• present active indicative
• from video, videre = to see

It matches puella, which is singular.

So puella videt = the girl sees.

Yes, tectum can refer to a roof and sometimes more generally to the covered part of a building. Depending on context, English might translate it as roof, and in some situations something like ceiling may be considered.

But in a sentence with drops stopping and then a girl noticing a small crack, roof is a very natural understanding.

Because Latin often puts a time clause first to set the scene before the main event.

So the sentence structure is:

• first: after the drops stopped falling
• then: the girl sees a small crack in the roof

This ordering is very natural in Latin, especially in narrative. It helps the reader understand the sequence of events clearly.

Yes. It is a standard and natural Latin construction:

• subject: stillae
• verb: desierunt
• complementary infinitive: cadere

Latin commonly expresses stop doing X with desino + infinitive, so this phrasing is straightforward and idiomatic.