Die probleem met die slot was klein; daarom het sy die deur weer oopgesluit.

Die is the Afrikaans definite article, meaning the. Afrikaans uses die for all nouns, regardless of gender, and also for plural nouns.

So here:

• die probleem = the problem
• die deur = the door

Unlike languages such as German or Dutch, you do not have to learn different definite articles for different genders.

In this sentence, slot means lock.

So:

• die probleem met die slot = the problem with the lock

That is the normal meaning here because the second clause talks about unlocking the door.

Yes, klein literally means small, but like English small, it can also mean minor or slight.

So Die probleem ... was klein means the problem was not serious or significant.

Also, after was, the adjective stays in its basic form:

• Die probleem was klein.

Daarom means therefore, for that reason, or that is why.

It introduces the result of the first clause:

• Die probleem ... was klein; daarom ...
• The problem ... was minor; therefore ...

The semicolon links two closely related full clauses. It is stronger than a comma but not as separate as a full stop. You could often replace it with a full stop in normal writing without changing the basic meaning.

This is because Afrikaans main clauses usually follow a verb-second pattern.

That means the finite verb must come very early in the clause, usually in the second position.

• Normal order: Sy het die deur weer oopgesluit.
• If you move daarom to the front: Daarom het sy die deur weer oopgesluit.

So when daarom comes first, the verb het comes next, and the subject sy comes after it.

This is a very common Afrikaans pattern.

Because this clause uses het plus a past participle.

In Afrikaans, when you form this kind of past tense:

• the auxiliary verb het appears near the beginning of the clause
• the main verb form goes to the end

So:

• het sy die deur weer oopgesluit

This is normal word order for Afrikaans perfect-tense clauses.

It is the perfect tense, formed with het + past participle.

Here:

• het = auxiliary verb
• oopgesluit = past participle

Afrikaans often uses this structure where English might simply use the simple past:

• she unlocked the door again

So even if the English translation is a simple past, the Afrikaans grammar is still the perfect construction.

Yes. The verb is oopsluit, meaning to unlock.

It is made from:

• oop = open
• sluit = lock / close

In meaning, oopsluit is unlock, not open and close.

In the past participle, Afrikaans inserts ge- into this compound form:

• oopsluit → oopgesluit

So oopgesluit is the normal past participle of oopsluit.

Weer here means again.

So:

• die deur weer oopgesluit = unlocked the door again

Its position is normal in Afrikaans. It comes before the participle oopgesluit and after the object die deur in this sentence.

You may also see slightly different placement in other sentences, depending on emphasis, but this position is very natural.

Here sy is the subject pronoun she.

You can tell because it stands by itself before/after the verb as the subject of the clause:

• daarom het sy ... = therefore she ...

This is different from possessive sy meaning his, which normally comes before a noun:

• sy deur = his door

So in this sentence, sy can only be understood as she.

It means unlock.

That is an important distinction:

• oopmaak = open
• oopsluit = unlock

So sy het die deur weer oopgesluit means she unlocked the door again, not necessarily that she physically pushed it open. The focus is on the lock, which matches the earlier phrase die probleem met die slot.