下列性质中，平行四边形具有而非平行四边形不具有的是（　　）

A．内角和为360°

B．外角和为360°

C．对角线互相平分

D．对角互补 ；

As a ( ) salesman, he can write and speak in foreign language, as well as sing and dance.

A．flexible

B．versatile

C．productive

D．sophisticated