Vorher ziehe ich meine Maske an, nachher öffne ich das Fenster.

Beforehand I put on my mask, afterwards I open the window.

Breakdown of Vorher ziehe ich meine Maske an, nachher öffne ich das Fenster.

• ich: I
• das Fenster: the window
• mein: my
• öffnen: to open
• anziehen: to put on
• vorher: beforehand
• die Maske: the mask
• nachher: afterwards

Questions & Answers about Vorher ziehe ich meine Maske an, nachher öffne ich das Fenster.

Why is it split as ziehe … an instead of the dictionary form anziehen?

Because anziehen is a separable verb. In main clauses, German keeps the finite verb in 2nd position and sends the separable prefix to the end:

• Main clause: Vorher ziehe ich meine Maske an.
• Subordinate clause (verb at the end, prefix reattaches): …, dass ich meine Maske anziehe.
• Perfect: Ich habe meine Maske angezogen.
• Infinitive with zu (zu goes between prefix and stem): …, meine Maske anzuziehen.

Why does the verb come before the subject in nachher öffne ich?

German main clauses are verb‑second. If you put a time adverbial like Nachher or Vorher first, it occupies the first slot, so the finite verb must be second and the subject follows:

• Nachher öffne ich das Fenster.
• If the subject comes first, it’s still verb‑second: Ich öffne nachher das Fenster.

Can I place the time adverbs inside the clause instead? For example, Ich ziehe vorher meine Maske an or Ich öffne das Fenster nachher?

Yes. Time adverbs can go first for emphasis or stay inside the clause. All of these are correct, with subtle differences in emphasis:

• Vorher ziehe ich meine Maske an.
• Ich ziehe vorher meine Maske an.
• Nachher öffne ich das Fenster.
• Ich öffne das Fenster nachher.
  A common neutral order is Time–Manner–Place within the clause.

What’s the difference between vorher/nachher and bevor/nachdem?

• vorher/nachher are adverbs; they do not introduce a clause.
• bevor/nachdem are subordinating conjunctions and require a full clause with the verb at the end.
  Paraphrases:
• Bevor ich das Fenster öffne, ziehe ich meine Maske an.
• Nachdem ich meine Maske angezogen habe, öffne ich das Fenster.
  Note with nachdem you normally use a perfect/pluperfect to show the earlier action is completed.

Do I need the future tense (werde öffnen) to talk about what happens next?

No. German often uses the present with time words to express the near future or a sequence:

• Nachher öffne ich das Fenster.
  The future (Ich werde das Fenster öffnen) is used mainly for predictions, assumptions, or emphasis, and can sound heavier here.

Is Maske anziehen the most idiomatic way to say “put on a face mask”?

For a protective face mask, the most idiomatic verb is aufsetzen:

• Ich setze (mir) die Maske auf.
  You’ll also hear (die Maske) anlegen in formal contexts. anziehen is fine for clothing (e.g., jacket, shirt) and is understandable for a mask, but aufsetzen is the default collocation for items worn on the head/face (hat, glasses, mask). For a cosmetic mask, use auftragen (“apply”).

What cases are meine Maske and das Fenster in?

Both are direct objects in the accusative case.

• (Ich) ziehe [was?] die/ meine Maske an → accusative.
• (Ich) öffne [was?] das Fenster → accusative.
  Grammar details:
• Maske is feminine; accusative singular is die/meine Maske (same form as nominative).
• Fenster is neuter; accusative singular is das Fenster (same as nominative).

Can I use aufmachen instead of öffnen?

Yes. aufmachen is more colloquial; öffnen is neutral to formal. With aufmachen (separable), you must split it in main clauses:

• Nachher mache ich das Fenster auf.
  Both mean “open the window.”

Where would a pronoun go? Would Vorher ziehe ich sie an be right?

Yes:

• Vorher ziehe ich sie an.
  Pronoun objects tend to come earlier in the middle field, before heavier nouns, and the separable prefix still goes to the end. If you had both dative and accusative pronouns, the usual order is accusative before dative (e.g., Ich gebe es ihm).

Are vorher and nachher capitalized?

As adverbs, they’re lowercase, except that the first word of a sentence is capitalized by default:

• Vorher (sentence-initial) …, nachher (mid-sentence).
  They’re capitalized only when used as nouns: das Vorher und Nachher.

Is the comma in the sentence required? Could I use a semicolon or a period?

Yes, the comma is required here because you’re placing two main clauses side by side without a conjunction. A semicolon or a period would also be correct:

• Vorher ziehe ich meine Maske an; nachher öffne ich das Fenster.
• Vorher ziehe ich meine Maske an. Nachher öffne ich das Fenster.
  If you connect them with und, you normally don’t use a comma: …, und nachher öffne ich …

Can I say the same thing with zuerst and dann?

Absolutely:

• Zuerst ziehe ich meine Maske an, dann öffne ich das Fenster.
  This pair is very common for step-by-step instructions.

What’s the nuance between nachher, danach, and später?

• nachher: “afterwards, shortly after (this)” in everyday speech.
• danach: “after that (step/event)”—more text‑linking and slightly more neutral/formal than nachher.
• später: “later” in a looser, less tied-to-the-previous-step sense.
  All three can work here; choose based on how tightly you want to link to the previous action.

Does the order of the two clauses matter for the meaning?

No. The time adverbs carry the sequence, so you can swap the clauses without changing the order of events:

• Nachher öffne ich das Fenster, vorher ziehe ich meine Maske an.
  What changes is only the emphasis and flow.

Could I say ein Fenster instead of das Fenster?

Yes, if you mean “a window (any one of them)” rather than a specific, contextually known one:

• Specific/unique in context: das Fenster
• Non‑specific: ein Fenster
  Both are grammatically fine; pick the article that matches your intent.