平行四边形的对称中心是______．
平行四边形的对称中心是两对角线的交点．
故答案为：两对角线的交点
看图填空。
1. It's . It's time for class.
2. It's . It's time for class.
3. It's . It's time for class.
4. It's . It's time for class.
企业的退货管理制度所归属的会计制度设计范畴是（）
A．职责分工控制制度设计
B．授权制度和审核批准制度设计
C．采购与验收控制设计
D．付款控制设计
. It's time for 
class.
. It's time for 
class. 
. It's time for 
class. 
. It's time for 
class.