She had been in a tight corner before and had always managed to cope.

a 是不定冠词，表示"一个"或"某种"。 tight 的意思是"紧的、狭窄的"，引申为"困难的、棘手的"。 corner 的意思是"角落"，引申为"困境、窘境"。 a tight corner 是一个固定短语，字面意思是"一个狭窄的角落"，比喻"困境、窘境"。