The teacher wrote a brief comment in the______to show the student why it was wrong.
【正确答案】 B
【答案解析】各项的意思是：manual手册，指南。margin页边空白；边缘；余地。edge边缘；刀刃；优势；经常指悬崖边上。verge边，边缘，界线(on the verge of接近于，濒临于)。根据句意判断，答案为B。