-That's the third time he's won the award in this field.

-Yes. He ________ his maximum potential in the past decade.[ ]

A．explored  

B．is exploring

C．has been exploring  

D．has explored

按建筑的( )来分，分为两大类，即生产性建筑与非生产性建筑。

A．类型
B．实质性质
C．生产性
D．作用