Quam diu muraena hamum mordet, puer lineam tenet.

Quam diu is a common Latin expression meaning as long as, while, or for as long a time as.

In this sentence, it introduces a time clause:

• Quam diu muraena hamum mordet = as long as the moray eel is biting the hook

So it tells you the time during which the action of the main clause happens.

Because muraena is in the nominative singular, which is the case normally used for the subject of a finite verb.

Here the verb is mordet, so:

• muraena = the one doing the biting
• hamum = the thing being bitten

A learner can often identify the subject in Latin by looking for the nominative noun and checking which noun makes sense with the verb.

They are direct objects.

• hamum mordet = bites the hook
• lineam tenet = holds the line

Both mordet and tenet are transitive verbs here, so they take a direct object in the accusative case.

That is why you get:

• hamus → hamum in the accusative singular
• linea → lineam in the accusative singular

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

So the second clause works like this:

• puer = subject
• lineam = direct object
• tenet = verb

Even though English often likes a more fixed order, Latin mainly shows these relationships through case endings.

Latin very often places the finite verb near the end of the clause, especially in straightforward prose. So:

• muraena hamum mordet
• puer lineam tenet

This is a very normal Latin word order pattern: subject + object + verb, though Latin is flexible and other orders are possible.

So the verb-final position is not mandatory, but it is common and natural.

Both mordet and tenet are present indicative active, third person singular.

Latin often uses the present tense here simply to describe what is happening:

• the eel bites
• the boy holds

With quam diu, the present tense is perfectly natural when the sentence describes an action occurring at the same time as another action.

Forms:

• mordet = he/she/it bites
• tenet = he/she/it holds

Because muraena and puer are both singular, the verbs are singular too.

Because this clause is just stating a straightforward fact of time: as long as the eel bites the hook, the boy holds the line.

In Latin, ordinary temporal clauses of this kind commonly take the indicative when they refer to a real or factual action. Nothing hypothetical, doubtful, or strongly dependent on another idea is being emphasized here, so the indicative is expected.

That is why you see:

• mordet, not a subjunctive form

Yes, to a large extent.

Because Latin uses case endings, these are still understandable:

• Quam diu hamum muraena mordet, puer lineam tenet
• Puer lineam tenet, quam diu muraena hamum mordet

The core relationships stay the same because:

• muraena is nominative
• hamum and lineam are accusative
• puer is nominative

However, changing word order can slightly change emphasis. Latin writers often move words around to highlight what matters most.

In practice, you should learn quam diu as a set phrase meaning how long? or as long as, depending on context.

You can analyze it historically:

• quam is related to how
• diu means for a long time

But for reading, it is usually best to recognize quam diu as a unit. In this sentence, it functions like the conjunction as long as.

Here are the basic forms you would look up:

• muraena, muraenae f. = moray eel
• hamus, hami m. = hook
• puer, pueri m. = boy
• linea, lineae f. = line, cord, fishing line
• mordeo, mordere, momordi, morsum = bite
• teneo, tenere, tenui, tentum = hold, keep

This helps you see where the sentence forms come from:

• muraena = nominative singular
• hamum = accusative singular
• puer = nominative singular
• lineam = accusative singular
• mordet from mordeo
• tenet from teneo

At the basic level, tenet means holds. In context, though, it can suggest keeps hold of, keeps taut, or maintains control of the fishing line.

So even if the English translation gives just holds, the Latin verb can feel a little stronger than a momentary touch. It suggests that the boy continues to keep the line in hand while the eel is biting the hook.