Learn Hardcore German: Ich werde auch das Büro pünktlich abschließen.

German main clauses follow the V2 rule: the finite verb (here werde) must occupy the second position. Since you’re using the future tense, the infinitive of the main verb (abschließen) is pushed to the very end. Even though abschließen is a separable‐prefix verb, in an infinitive it stays together.

What kind of verb is abschließen, and why doesn’t the prefix separate here?

abschließen is a separable‐prefix verb composed of ab- + schließen. In finite forms in present or simple past, the prefix detaches and moves to the end (e.g. Ich schließe das Büro ab.). But in an infinitive (especially with werden), the prefix remains attached and the whole verb sits at the end.

What does auch mean here, and how does its position affect the emphasis?

auch means “also” or “too.” Placed before das Büro, it tells us the office is an additional object that will be locked/finished. If you move auch elsewhere, you shift the focus:

Ich werde das Büro auch pünktlich abschließen. (“I will lock the office on time as well [among other things].”)
Ich werde das Büro pünktlich auch abschließen. (Unusual; sounds like “on time, I’ll also lock the office.”)

Why is das Büro in the accusative case?

das Büro is the direct object of abschließen—it receives the action. The accusative neuter form of das Büro is identical to the nominative, but its case role is accusative here.

Is pünktlich an adjective or an adverb in this sentence? Why isn’t it inflected?

Here pünktlich acts as an adverb, modifying abschließen (“on time”). Adverbs in German are uninflected, so you see the bare form pünktlich, not pünktliche or pünktlichem.

Does abschließen here mean “to lock” or “to finish (up)”?

Both are possible: abschließen can mean “to lock up” or “to complete/finish.” With das Büro, context usually suggests “to lock up the office” at closing time. If you were talking about a project, it might mean “to finish the office project.”

Could I express the same idea in the present tense?

Yes. German often uses the present to talk about the future when the time reference is clear. You could say: Ich schließe auch das Büro pünktlich ab. This sounds perfectly normal and implies the same future action.

Can I change the word order and still be correct?

You have flexibility, but each order can slightly shift emphasis. Valid options:

Ich werde auch das Büro pünktlich abschließen.
Ich werde das Büro auch pünktlich abschließen.
Ich werde das Büro pünktlich abschließen. Avoid splitting the infinitive or moving abschließen from the end.