obwohl, trotzdem, sodass

You already use trotzdem. Its partner is obwohl, and the two say almost the same thing from opposite ends of the sentence.

obwohl is a conjunction: verb to the end. trotzdem is an adverb: verb straight after. Same idea, opposite machinery.

• Obwohl ich müde war, habe ich weitergearbeitet.

  Although I was tired, I kept working.

  war at the end of the obwohl-clause, then habe opening the main clause

• Ich bin spazieren gegangen, obwohl es geregnet hat.

  I went for a walk although it was raining.

  the obwohl-clause can come second just as easily

• Ich war müde, trotzdem musste ich arbeiten.

  I was tired; all the same I had to work.

  trotzdem keeps the verb in position 2

Which one you need depends on which half you want in the clause. The unexpected thing goes in the main clause either way; obwohl marks the obstacle, trotzdem marks the outcome.

Now the opposite relationship: a consequence. German has two shapes, and they are not interchangeable.

sodass introduces the result of the whole sentence. so + adjective + dass says the quality was extreme enough to cause it.

• Der Zug hatte Verspätung, sodass ich meinen Anschluss verpasst habe.

  The train was late, with the result that I missed my connection.

  sodass is subordinating: verb to the end

• Es war so laut, dass ich nichts verstehen konnte.

  It was so loud that I could not understand anything.

  so sits with the adjective, dass opens the clause

• Die Wohnung war so teuer, dass wir abgesagt haben.

  The flat was so expensive that we pulled out.

Compare the three relationships one last time, because B1 asks you to pick between them under pressure: