How old are Duan and Sang Zhi?

Duan and Sangzhi are eight years apart. In the novel You Can't Hide Secretly, Duan was born in 1989 and Sang Zhi was born in 1997. Because of his age, Duan has always taken care of Sangzhi as his sister, and Sangzhi has long liked Duan. The passage "Can't Hide Secretly" praised his family background: he was born in a well-off family and was originally happy, but he fell into a trough after his father committed suicide. Duan's father hit people after drinking. At that time, out of fear, he did not send someone to the hospital, but fled the scene. Duan praised his father for committing suicide, but his father refused to accept legal sanctions and committed suicide by jumping off a building. Duan praised him for taking on his father's sins.