定和值尾和跨度的公式简介：After Su Can chatted with his three roommates, he walked out of the balcony and closed the curtains to block out the bustle of the dormitory. Only then did he call Cheng Keshu.
After Su Can chatted with his three roommates, he walked out of the balcony and closed the curtains to block out the bustle of the dormitory. Only then did he call Cheng Keshu.
