"Can the teacher understand?"
Translation:선생님은 이해할 수 있습니까?
I am native Korean, but I feel this sentence unfamiliar. That is because of the Honorifics. 선생님 is usually the one to whom we should use honorific expressions. So I recommend the sentence 선생님께서는 이해하실 수 있습니까?. However the sencentce 선생님은 이해할 수 있습니까? is not a wrong sentence, but it sounds rude.
Thanks for your input.
True, it is important to learn these honorifics and I hope they will be included in a separate section later on by the course creators. You can get by without, but to truly become fluent one should use them properly, otherwise, you'll get stuck in the "he's a foreigner so it's ok for him to be unknowingly rude" beginner level ;)