Ons sper die struikelgevaar met die versperring af.

Because the full verb is afsper, which is a separable verb in Afrikaans.

In a normal main clause:

• the conjugated part goes near the beginning: sper
• the separable particle goes to the end: af

So:

• Ons sper ... af.

This is very similar to verbs in Dutch and German, and a bit like English phrasal verbs such as seal off or block off, except Afrikaans follows the split more systematically.

It is one verb lexically, so you would usually look it up as afsper in a dictionary.

But in actual sentences, it can appear:

• split in a main clause: Ons sper ... af
• together in other forms, such as:
  • infinitive: om af te sper
  • past participle: afgesper

So it is best to think of it as one separable verb.

It is a compound noun, which Afrikaans uses very often.

It breaks down as:

• struikel = stumble / trip
• gevaar = danger / hazard

So literally it is something like stumbling danger, but natural English would usually be trip hazard.

In Afrikaans, long compounds like this are completely normal and are usually written as one word.

Because both nouns are definite:

• die struikelgevaar = the trip hazard
• die versperring = the barrier

Afrikaans die is much simpler than English articles in some ways:

• it is the definite article
• it is used for singular and plural
• it does not change for grammatical gender

So the same word die works for many different nouns.

Here met means with or by means of. It introduces the thing used to do the action.

So met die versperring tells you the means/instrument:

• we are blocking it off with the barrier

That is the most natural choice here. A word like deur would usually be used more for an agent in a passive-type idea, not for a tool like this.

Normally, the given sentence order is better:

• Ons sper die struikelgevaar met die versperring af.

The reason is that with a separable verb, the particle af usually stays at the end of the clause. So other material, such as met die versperring, normally comes before af.

An English speaker may want to place af earlier because of English cordon off the hazard with the barrier, but standard Afrikaans usually keeps af at the end in this kind of sentence.

Yes. They belong to the same general family of meanings about blocking or obstructing.

• sper / afsper = to block off, cordon off
• versperring = a barrier, obstruction, roadblock, or blocking structure

So in this sentence:

• afsper is the action
• versperring is the thing used to carry out that action

That makes the wording feel very natural in a safety or official context.

You would usually say:

Ons sper nie die struikelgevaar met die versperring af nie.

Afrikaans typically uses double negation:

• the first nie comes after the finite verb
• the second nie comes at the end of the clause

So the pattern is:

• Ons sper nie ... af nie.

This is one of the most important sentence patterns in Afrikaans.

The most natural past form in Afrikaans is the perfect tense:

Ons het die struikelgevaar met die versperring afgesper.

Notice what happens:

• het is the finite verb near the beginning
• afgesper goes to the end

The separable verb is now written together as the past participle:

• afsper → afgesper

Afrikaans usually prefers this kind of past construction instead of a simple past form.

In practice, it can refer to the hazardous situation or to the thing that creates the hazard, much like English trip hazard.

So in a safety context, die struikelgevaar can naturally mean:

• the dangerous obstacle
• the risky area
• the hazard that needs to be marked off or blocked off

That is why it works well as the direct object of afsper in this sentence.