Die optometris begin die oogtoets.

Because die is the normal definite article in Afrikaans, and it is used for the in front of nouns.

So in this sentence:

• Die optometris = the optometrist
• die oogtoets = the eye test

Unlike English, Afrikaans does not change the definite article for gender or case. It is just die in all of these situations.

In everyday Afrikaans, die most often means the.

However, depending on context, die can sometimes point something out in a way that feels a bit like that/those in English. But in a simple sentence like this one, you should understand it as the.

If you specifically want this, Afrikaans usually uses hierdie.

• hierdie oogtoets = this eye test

Yes. Optometris is very close to English optometrist, so it is an easy word to recognize.

A lot of Afrikaans vocabulary is either cognate with English or similar enough to be guessed from context. Here, the spelling is just slightly different:

• English: optometrist
• Afrikaans: optometris

Because Afrikaans usually follows a subject–verb–object pattern in a normal main clause, just like English.

So the sentence breaks down as:

• Die optometris = subject
• begin = verb
• die oogtoets = object

That gives:

• The optometrist
  • begins
    • the eye test

This is the normal word order for a basic statement.

Afrikaans verbs do not usually change form depending on the subject the way English verbs do.

In English:

• I begin
• he begins
• they begin

In Afrikaans, the verb usually stays the same:

• ek begin
• hy begin
• hulle begin

So begin works with die optometris without any extra ending.

Very close, yes. Begin in Afrikaans means begin/start.

In this sentence, begin die oogtoets means begins the eye test or starts the eye test.

Afrikaans often has pairs like this where the word looks very familiar to an English speaker.

Oogtoets is a compound noun:

• oog = eye
• toets = test

So oogtoets literally means eye test.

Afrikaans very often writes compound nouns as one word, where English often uses two words. This is a very important spelling habit to get used to.

Compare:

• Afrikaans: oogtoets
• English: eye test

You will see this a lot in Afrikaans.

A rough pronunciation guide is:

• oog sounds something like the vowel in Scottish loch is not right here; a better English-friendly approximation is a long ohkh sound, but the final g is a guttural Afrikaans sound that English does not really have.
• toets sounds roughly like toots but with a slightly different vowel quality.

A practical learner-friendly approximation is something like:

• ohkh-toots

But the most important thing is that the g in oog is the typical Afrikaans guttural sound, not a normal English g.

Because begin can directly take an object in Afrikaans, just as start can in English.

So:

• begin die oogtoets = begin/start the eye test

You do not need an extra preposition here.

Compare English:

• The optometrist starts the eye test.

That is the same structure.

Yes. It can be used both ways.

For example:

• Die optometris begin. = The optometrist begins / starts.
• Die optometris begin die oogtoets. = The optometrist begins the eye test.

In the sentence you were given, the speaker includes the object die oogtoets to show what is being started.

A very common past form in Afrikaans uses het plus a past participle.

So you would usually say:

• Die optometris het die oogtoets begin.
• The optometrist began / has begun the eye test.

Notice that:

• het comes after the subject
• begin moves to the end

This is a very common Afrikaans pattern.

In a yes/no question, Afrikaans usually puts the verb first.

So:

• Begin die optometris die oogtoets?
• Is the optometrist beginning the eye test? / Does the optometrist begin the eye test?

That verb-first pattern is very common in Afrikaans questions.

Typically:

• oogtoets → oogtoetse
• optometris → optometriste

So for example:

• Die optometris begin die oogtoets.
• Die optometriste begin die oogtoetse.

This is useful because plural forms in Afrikaans are not always the same as English, and compound nouns still usually stay as one written word.