A:At home.
B:At school.
C:In a restaurant.
在▱ABCD中,AB、BC、CD三条边的长度分别为(a﹣3)cm、(a﹣4)cm、(9﹣a)cm,则这个平行四边形的周长为 ____cm.
_____ he was very tired, he continued working in his office.