Hulle onthou die daad.

Here, hulle means they.

It is the subject of the sentence, so Hulle onthou ... = They remember ...

A useful extra point: hulle can also be used for them in other contexts, but in this sentence it is clearly they because it comes before the verb.

Yes. In this sentence, die is the definite article, so die daad means the deed / the act.

A few important things about die:

• Afrikaans uses die for all genders
• It is also used with singular and plural nouns
• So Afrikaans does not change the article the way languages like German do

Also, die here is not the English verb die. It is usually pronounced roughly like dee.

Because Afrikaans verbs usually do not change according to the subject in the present tense.

So you get:

• Ek onthou = I remember
• Jy onthou = you remember
• Hy/Sy onthou = he/she remembers
• Hulle onthou = they remember

This is simpler than English, where you have I remember but he remembers.

Yes. This sentence follows the basic subject–verb–object order:

• Hulle = subject
• onthou = verb
• die daad = object

So the structure is very similar to English:

• They remember the deed
• Hulle onthou die daad

That said, Afrikaans does have verb-second word order in main clauses, so if something else comes first, the verb still stays in second position:

• Vandag onthou hulle die daad. = Today they remember the deed.

Daad means deed, act, or sometimes action, depending on context.

It often sounds a little more formal or weighty than a very everyday word. In many contexts, daad suggests a notable action or something someone has done.

Its plural is dade:

• die daad = the deed
• die dade = the deeds

You would usually use the Afrikaans double negative:

Hulle onthou nie die daad nie.

Afrikaans commonly places:

• one nie after the verb or verb phrase
• a second nie at the end of the clause

That is a very standard Afrikaans pattern.

For the past, Afrikaans very often uses the perfect:

Hulle het die daad onthou.
= They remembered / They have remembered the deed.

For the future:

Hulle sal die daad onthou.
= They will remember the deed.

So the key helpers are:

• het for the common past/perfect form
• sal for the future

Because onthou begins with the prefix ont-, and verbs with prefixes like ont-, be-, ver-, and her- normally do not take ge- in the perfect participle.

So you say:

• Ek het dit onthou
• Hulle het die daad onthou

not:

• geonthou

This is an important pattern to remember in Afrikaans.