As jy die slot nie kan oopsluit nie, bel die tegnikus asseblief.

Because standard Afrikaans normally uses double negation.

In this sentence, the negative part is framed by nie ... nie:

• As jy die slot nie kan oopsluit nie
  = If you cannot unlock the lock

A simple way to think of it is:

• the first nie introduces the negation
• the second nie closes the negated clause

This is one of the most noticeable differences from English, which usually uses only one not.

Because As introduces a subordinate clause, and Afrikaans changes the verb order in subordinate clauses.

In a main clause, you would get something like:

• Jy kan die slot nie oopsluit nie.
  = You cannot unlock the lock.

After as meaning if, the verb part moves toward the end:

• As jy die slot nie kan oopsluit nie ...

So in this clause, kan oopsluit appears near the end, with the second nie closing the clause.

Here as means if.

So:

• As jy ... nie ... nie = If you do not / cannot ...

Be careful, because as can also mean than in comparisons:

• groter as = bigger than

So the meaning depends on context. In your sentence, it is clearly the conditional if.

Because bel die tegnikus asseblief is an imperative: a command or instruction.

Afrikaans usually forms the imperative with the base form of the verb:

• Bel die tegnikus.
  = Call the technician.

Just like in English, the subject you is usually omitted in commands. So Afrikaans does not need jy there.

Also, in this context bel means call / phone, not ring.

Because after a modal verb like kan (can), Afrikaans uses the next verb directly.

So you say:

• kan oopsluit = can unlock

not:

• kan om te oopsluit ✘

This is similar to English:

• can unlock
• not can to unlock

Yes, oopsluit is one word here.

It is a compound/separable verb built from:

• oop = open
• sluit = lock / close

Together, oopsluit means unlock.

In forms like the infinitive or after a modal verb, it stays together:

• kan oopsluit

With some finite verb patterns, Afrikaans separable verbs can split, so learners may later see related patterns where the pieces are not together.

Because die is the definite article, meaning the.

Afrikaans uses:

• die = the
• 'n = a / an

So:

• die slot = the lock
• die tegnikus = the technician

Afrikaans does not change the article for gender, so die works for all nouns in the singular definite form.

Yes, asseblief can move.

In commands, it is very common at the end:

• Bel die tegnikus asseblief.

But you can also say:

• Bel asseblief die tegnikus.

Both are natural. Putting asseblief at the end often sounds especially smooth and polite in instructions.

Because the sentence begins with a subordinate if-clause:

• As jy die slot nie kan oopsluit nie, ...

That clause is followed by the main clause:

• bel die tegnikus asseblief.

Afrikaans normally uses a comma to separate an introductory subordinate clause from the main clause, much like English does in sentences such as:

• If you can't unlock the lock, please call the technician.

Jy is the normal word for you in everyday Afrikaans.

• jy = normal singular you
• u = formal/polite you

In many modern instructions, everyday statements, and general advice, jy is very common and sounds natural. U is more formal and is often used in very polite, official, religious, or customer-facing language.

So this sentence sounds direct but still polite, especially because of asseblief.

In this sentence, yes: slot means lock.

That is clear because of the verb oopsluit, which means unlock. So die slot oopsluit is naturally unlock the lock.

As a learner, it is useful to notice that the surrounding words often tell you which meaning is intended.