结构推理 尽管他已经退休5年了，但他在学术界仍然很活跃。(to remain active in)
【正确答案】It is 5 years since his retirement, but he has remained active in academic circles.
【答案解析】[翻译指导] 注意although不能和but连用。“学术界”还可翻译为the academic field。