You Chose Bai Yueguang. What Does It Have to Do with Me Getting the Certificate?

In his previous life, Yang Chen loved Lin Zixiao crazily and humbly. She spent half her life silently, but in the end, she married someone else, causing him to die in depression. Now, he was reborn back to his junior year, on his birthday. At this time, his girlfriend forgot his birthday, but was dating her Bai Yueguang. Yang Chen secretly vowed not to be a licking dog anymore. A word of separation completely severed the relationship between Lin Zixiao and him. But at this time, he awakened to a system. The system told him that he could only stay in this world for one day! In order to be able to stabilize in this world, he began to complete system tasks crazily. However, the system inexplicably bound the partner to that woman...