Capulator concam tenet quasi oleum iam purum sit.

A good way is to look for a complete statement first:

• Capulator concam tenet = a complete main clause
• quasi oleum iam purum sit = a subordinate clause introduced by quasi

So the structure is:

• main clause: capulator concam tenet
• comparison/appearance clause: quasi ... sit

In other words, quasi signals that what follows is not a new independent statement, but something like as if ...

Capulator is nominative singular, and it is the subject of tenet.

For a learner, one useful clue is the ending -tor. Many Latin agent nouns end in -tor and are masculine nominative singular in that form, for example orator, imperator, lator. So capulator looks like the person who does X and fits naturally as the subject.

Because it is the direct object of tenet.

The verb tenet means holds and normally takes something being held. In this sentence, that thing is concam, so it appears in the accusative singular.

So the basic pattern is:

• capulator = subject
• concam = direct object
• tenet = verb

Tenet is:

• 3rd person singular
• present tense
• active voice
• indicative mood

It comes from tenere.

So grammatically it means he/she/it holds or is holding, depending on context.

Here quasi introduces a comparison of appearance or attitude: as if, as though.

It tells you that the speaker is not simply stating that the oil is pure. Instead, the action in the main clause is being described in a way that makes it seem as if the oil were already pure.

So quasi is a signal that the following idea is being presented as a comparison, impression, or supposition.

Because after quasi in the sense as if / as though, Latin often uses the subjunctive.

So:

• est = indicative, a straightforward statement of fact
• sit = subjunctive, used here for a supposed or imagined situation

That is why quasi ... sit means something like as if ... were/is rather than a flat statement ... is.

Sit is the present subjunctive of esse.

In a sentence like this, the present subjunctive can show a situation viewed as simultaneous with the main verb tenet. The sense is roughly as if the oil is already pure from the point of view of the action happening now.

An imperfect subjunctive like esset could also appear in some contexts, especially depending on style, tense sequence, or how the comparison is being framed. But here sit keeps the subordinate idea closely tied to the present-time main verb tenet.

Because oleum is the subject of sit, not the object of tenet.

That is a very common thing for English speakers to miss at first, because the sentence has two clauses:

1. Capulator concam tenet
2. quasi oleum iam purum sit

In the second clause, oleum is what sit is talking about. So it is nominative singular.

Purum agrees with oleum.

Both are:

• nominative
• singular
• neuter

That is because purum is a predicate adjective with sit. Latin uses agreement here just as it does elsewhere: the adjective matches the noun it describes.

So in the clause:

• oleum = subject
• purum = predicate adjective describing the subject

Because it does not go with concam and it is not a direct object.

It belongs to the quasi clause, where it works with sit:

• oleum ... sit
• purum describes oleum

With forms of esse, Latin uses a predicate noun or adjective that agrees with the subject, rather than an object in the accusative.

So oleum purum sit means the oil be pure, not someone makes the oil pure.

Iam means already and modifies the idea of the oil being pure.

So the sense is:

• not just as if the oil were pure
• but as if the oil were already pure

Its placement before purum helps highlight that state: already pure.

Because Latin word order is much freer than English word order.

English depends heavily on position:

• subject + verb + object

Latin depends much more on endings. Since the endings show what each word is doing, Latin can move words around for emphasis, rhythm, or style.

This sentence is still easy to parse because the forms tell you the grammar:

• capulator = subject
• concam = object
• tenet = verb
• oleum ... purum sit = subordinate clause

So even though the order is not the most English-like order, the endings keep the meaning clear.

Because Latin does not have articles like English does.

So a noun like capulator can mean:

• the capulator
• a capulator

and concam can mean:

• the basin
• a basin

The context tells you which one is more natural in translation.

Yes in form, though it may be less common or more technical in vocabulary than very basic textbook words.

The ending -tor is very typical for an agent noun, meaning a person who does something. So even if the word itself is unfamiliar, its shape gives you a grammatical clue:

• masculine
• nominative singular
• probably the doer of the action

That is a useful reading strategy in Latin: even when a word is rare, its ending often still tells you a lot.