I wrote "While I was going home it was snowing". I understand that yağdı is not in continuous tense, but what could be the difference between "it was snowing" and "it snowed"? Or does this course want to teach us to translate word-by-word instead of understanding the sentence, and to compound it on the other language?
There's no reason not to use simple past + simple past. See some comments here
It's easy to come up with valid examples: "While he played piano, I sat and listened", "While I listened, I became bored",
This is a problem with several several questions on here with -rken and different tenses