"Grandfather sleeps in the car."
Translation:할아버지께서 차에서 주무십니다.
주무세요 (주무시다 + ~어요) should also be accepted because the sentence is about a grandfather not directed to him.
I can't get past this level because some answers need 할아버지/할머니 and some need 할아버님/할머님 as far as I know the only difference is how respectful you are being and that generally you would refer to someone else's grandparent with 님. Can anyone tell me if there should be a way to know which to use or if this particular course is just too selective.