Caementum foramen obstruit, sed aqua manat.

This is a very good question, because in this clause the forms are a little tricky.

• caementum can be either nominative singular or accusative singular
• foramen can also be either nominative singular or accusative singular
• obstruit means he/she/it blocks or blocks

So, based on form alone, the clause is technically ambiguous. In practice, the meaning shown to the learner tells you that:

• caementum = the subject
• foramen = the direct object

So the sense is the cement blocks the hole.

This is possible in Latin because:

1. neuter nouns often have the same form in the nominative and accusative singular
2. Latin word order is more flexible than English
3. context often resolves ambiguity

Latin word order is much freer than English word order.

In English, you usually need:

• subject + verb + object
  → The cement blocks the hole

In Latin, you can often move words around without changing the basic meaning, because the grammatical roles are usually shown by endings rather than position.

So:

• Caementum foramen obstruit
• Caementum obstruit foramen
• Foramen caementum obstruit

can all potentially express the same basic idea, although the emphasis may shift.

Here, putting foramen before obstruit is perfectly natural Latin.

In this sentence, foramen is the direct object, so it is functioning as an accusative singular.

A useful thing to know is that foramen is a third-declension neuter noun. For neuter nouns:

• nominative singular and accusative singular are the same

So foramen could look nominative or accusative, but here it is understood as accusative because it is the thing being blocked.

Both are present tense, third person singular, active voice, indicative mood.

So:

• obstruit = blocks / is blocking
• manat = flows / is flowing / leaks

Latin present tense can often be translated in more than one way in English, depending on context.

Aqua is the subject of the second clause:

• sed aqua manat = but water flows / but water leaks

Because it is the subject, it is in the nominative singular.

This one is clearer than the first clause, because aqua has a distinct nominative form, and manat is a singular verb that agrees with it.

Sed means but.

It is a coordinating conjunction joining two independent clauses:

• Caementum foramen obstruit
• sed aqua manat

So it shows contrast:

• the cement blocks the hole,
• but water still flows/leaks.

Classical Latin does not have articles like English the and a/an.

So a noun like caementum can mean:

• cement
• the cement
• a cement

depending on context.

Likewise:

• foramen = hole / the hole
• aqua = water / the water

English usually requires an article, but Latin usually does not.

They belong to different declensions:

• caementum: second declension neuter
• foramen: third declension neuter
• aqua: first declension feminine

That matters because each declension has its own pattern of endings.

For example:

• second-declension neuter nouns often end in -um in the nominative singular
• third-declension neuter nouns often have varied nominative forms, such as foramen
• first-declension nouns often end in -a in the nominative singular

In Latin, verbs agree with the subject in person and number, not in whether it is human.

So a singular thing still takes a third-person singular verb.

• caementum obstruit = the cement blocks
• aqua manat = the water flows

English does the same thing:

• the cement blocks
• the water flows

Even though these are not people, they still use the same third-person singular verb form.

Yes. Depending on context, manat can be rendered in English as:

• flows
• is flowing
• runs
• leaks
• trickles

The exact English choice depends on what kind of situation is being described. In a sentence about a blocked hole and water, leaks or flows may both make sense.

It is one sentence made up of two coordinated clauses:

1. Caementum foramen obstruit
2. sed aqua manat

They are linked by sed = but.

So it is not two separate sentences, but one compound sentence with a contrast between the two parts.