It's the stage in the middle of the journey when people feel youth vanishing, their prospects narrowing and death approaching.
这是人生旅途的中间阶段，在这个阶段，人们感觉到青春的消逝，前景的逐渐狭窄，死亡的逼近。
2
A survey done by the China Youth and Children Research Center showed that school accidents kill more elementary and middle school students than anything else.
中国青少年研究中心的一项调查显示，学校事故是导致小学生和中学生死亡的最大原因。
3
The Youth Climate Summit, a week-long festival of climate action for primary and middle schools in the UK, starts on 9 November.