Subordinate Clauses II: Temporal Clauses with 'bevor', 'nachdem', 'seit'

Welcome to our lesson on temporal subordinate clauses.
In German, when you want to specify when something happens in relation to another event, you use temporal subordinate clauses (Temporalsätze). You are already familiar with 'als' (for a single past event) and 'wenn' (for repeated or future events). Today, we will expand our toolkit with three more essential temporal conjunctions: 'bevor', 'nachdem', and 'seit'. These conjunctions help us describe the sequence of events with much greater precision.

▶️ Bevor (before)
'Bevor' is used to indicate that the action in the main clause happens after the action in the subordinate clause. In simpler terms, the action in the 'bevor'-clause must be completed before the action in the main clause can begin.
The structure is straightforward: 'bevor' introduces the subordinate clause, and the conjugated verb is sent to the very end of that clause.

🔹 Tense Rule: The tenses in the main clause and the 'bevor'-clause are usually the same (this concept is called Gleichzeitigkeit).

• Präsens + Präsens: Ich putze meine Zähne, bevor ich ins Bett gehe. (I brush my teeth before I go to bed.)
• Präteritum + Präteritum: Er las das Buch, bevor er den Film sah. (He read the book before he saw the movie.)

Remember, if the subordinate clause comes first, the main clause starts with its verb:

• Bevor ich ins Bett gehe, putze ich meine Zähne.

▶️ Nachdem (after)
'Nachdem' is the logical opposite of 'bevor'. It indicates that the action in the main clause happens after the action in the subordinate 'nachdem'-clause has already been completed.

❗️ The Golden Rule of 'Nachdem': Tense Shift!
This is a critical concept called 'Vorzeitigkeit' (anteriority). Since the action in the 'nachdem'-clause happened before the action in the main clause, its tense must be "one step further in the past".

🔹 Main Clause in Present (Präsens) → 'Nachdem'-clause in Perfect (Perfekt)
This describes a past completed action and its present result.

• Ich trinke einen Kaffee, nachdem ich aufgestanden bin. (I drink a coffee after I have gotten up.)
  (First: getting up is completed. Then: drinking coffee now.)

🔹 Main Clause in Simple Past (Präteritum) → 'Nachdem'-clause in Past Perfect (Plusquamperfekt)
This describes two sequential actions that both happened in the past.

• Sie ging nach Hause, nachdem sie die Arbeit beendet hatte. (She went home after she had finished the work.)
  (First: finishing work was completed in the past. Then: going home happened, also in the past.)

▶️ Seit / Seitdem (since)
'Seit' (or its longer, interchangeable form 'seitdem') connects a starting point in the past with a situation that continues into the present. It answers the question "Since when?".

🔹 Tense Rule: The action in the 'seit'-clause is in a past tense (Präteritum or Perfekt), while the action in the main clause is typically in the present tense (Präsens). This highlights the ongoing result.

• Seit er in Berlin wohnt, ist er viel glücklicher. (Since he has lived in Berlin, he is much happier.)
  (The living in Berlin started in the past; the happiness continues now.)
• Wir haben uns nicht mehr gesehen, seitdem wir die Schule beendet haben. (We haven't seen each other since we finished school.)
  (Finishing school was in the past; not seeing each other is the present state.)

💡 Summary of Time Relationships

• bevor: Action 2 happens before Action 1. (Same Tense)
  → Bevor du gehst, ruf mich an.
• nachdem: Action 2 happens after Action 1. (Tense Shift: one step back)
  → Nachdem du gegangen warst, rief ich sie an.
• seit: Action 1 started in the past and Action 2 is the ongoing result. (Past → Present)
  → Seit du hier bist, ist alles besser.

Mastering these conjunctions is a key step towards fluent, natural-sounding German. Pay close attention to the tense rules, especially with 'nachdem', as it is a common topic in B1 exams.