Real situations, full toolkit

No new grammar. This unit is about reaching for the right tool quickly, which is a different skill from knowing the tool exists.

Problem → Präteritum + weil/deshalb. Request → Konjunktiv II. Purpose → um…zu / damit. Description → adjective endings + relative clause.

Start with the one you will use most: explaining a problem properly. Three moves — what happened, what it meant for you, what you would like now.

• Mein Zug hatte Verspätung, deshalb habe ich den Termin verpasst.

  My train was delayed, so I missed the appointment.

  Präteritum for haben, Perfekt for the ordinary verb

• Ich konnte nicht anrufen, weil mein Handy kaputt war.

  I could not call because my phone was broken.

• Könnten wir einen neuen Termin machen?

  Could we make a new appointment?

Then describing something. This is where the adjective endings and the relative clauses earn their keep — together, in one sentence.

• Ich suche eine ruhige Wohnung, die nicht zu teuer ist.

  I am looking for a quiet flat that is not too expensive.

• Das ist der Kollege, mit dem ich jeden Tag arbeite.

  That is the colleague I work with every day.

• Mein neuer Chef ist ein Mann, der sehr viel fragt.

  My new boss is a man who asks a great many questions.

And purpose — the question wozu?, what something is for. Same subject takes um … zu; a second subject takes damit.

• Ich schreibe Ihnen, um einen Termin zu vereinbaren.

  I am writing to you in order to arrange an appointment.

  the standard opening of a formal German email

• Ich rufe an, damit Sie Bescheid wissen.

  I am calling so that you know.

Finally, keep the passive in your reading toolkit and use it sparingly in production: Das Auto wird gerade repariert is a complete, natural answer to "where is your car?".