C675 What's going on(part ii)

"I know your ID card has been renewed for one year, and I know who you are teaching here for!" became more and more agitated, and in the end, he covered his face and scolded loudly, "How do you know the time of my month?!"

"That's true. Back then when I was staying in your teacher's dormitory, you came here for a month. I calculated it like this two months later, if I'm not wrong