Aliquot pueri intro currunt, quia imber subito cadit.

Aliquot means several or some number of. It is an indeclinable word, which means it does not change its ending to match the noun.

So in aliquot pueri, only pueri shows the grammatical information. Aliquot simply adds the idea of an unspecified small number.

Pueri is the nominative plural of puer.

That tells you two things:

• nominative = it is the subject
• plural = more than one boy

So pueri currunt means the boys run or boys are running.

Because the endings match in number:

• pueri = plural subject
• currunt = 3rd person plural verb

Currunt comes from currere, meaning to run. The ending -unt tells you they run / they are running.

Latin present tense often covers both:

• simple present: they run
• progressive present: they are running

English usually separates those two ideas, but Latin often does not. Context tells you which is more natural.

Here intro is an adverb, meaning inside or inward.

So intro currunt means they run inside. Latin often uses a simple adverb where English might use something like into the house or indoors.

Because it is an adverb here, it does not take an object.

Yes, but it would not be exactly the same structure.

• intro currunt = they run inside / indoors
• in domum currunt or similar wording = they run into the house

So intro gives the direction inward without naming a specific place. It is a compact, natural way to express motion indoors.

Latin has no articles exactly like English the, a, or an.

That means:

• pueri can mean the boys or just boys
• imber can mean the rain or simply rain

The exact English wording depends on context. In this sentence, English will usually add articles because English normally requires them.

Quia introduces a reason clause. It means because.

So the structure is:

• main clause: Aliquot pueri intro currunt
• reason clause: quia imber subito cadit

In other words, the boys run inside because the rain suddenly falls.

Cadit is present active indicative, 3rd person singular, from cadere.

After quia, Latin normally uses the indicative when the reason is presented as a real fact. Here the speaker is simply stating what is happening: the rain is falling.

So quia imber subito cadit is a straightforward factual clause.

Imber is a common Latin noun meaning rain, often especially a rainstorm or shower.

It is the subject of cadit:

• imber = rain
• cadit = falls

Latin often expresses rain with the idea of falling, so imber cadit is very natural.

Imber is nominative singular here.

It is the subject of cadit, which is singular:

• imber = singular noun
• cadit = singular verb

So the grammar matches just as pueri matches currunt in the first clause.

Subito is an adverb, meaning suddenly.

It modifies cadit, telling you how the rain falls. So imber subito cadit means the rain suddenly falls or more naturally it suddenly starts raining.

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

This sentence has a very natural arrangement:

• Aliquot pueri first: introduces the subject
• intro currunt next: gives the action
• quia... after that: gives the reason

You could move some words around, especially subito, without changing the basic meaning. But the given order is clear and idiomatic.