Conjunctions
Connect words, phrases, and clauses
German conjunctions split into two families, and the difference is not meaning — it is WORD ORDER. COORDINATING (und, aber, oder, denn, sondern): they simply join two main clauses and do not count as a sentence element. The verb stays in second position, exactly as it was. Ich bleibe hier, denn ich BIN müde. SUBORDINATING (weil, dass, wenn, als, ob, obwohl, damit): they open a subordinate clause and push the conjugated verb all the way to the END. Ich bleibe hier, weil ich müde BIN. Same meaning in both examples. Completely different verb position. This is the single most visible marker of whether someone has internalised German sentence structure.
Persian word order does not move the verb when you add «چون» or «که» — «میمانم چون خستهام» keeps everything in place. German does move it, and the temptation to say «weil ich bin müde» is very strong precisely because it matches Persian. Train the reflex: the moment you say weil, dass or wenn, the verb is already booked for the end of the clause.