十三妹：媽媽65歲了，還能背出元素化合價，北大的我早忘了My mother is 65 years old, she can still recite the valence of elements.

凉子访谈录 - 十三妹：媽媽65歲了，還能背出元素化合價，北大的我早忘了My mother is 65 years old, she can still recite the valence of elements.