题干
— That’s the third time he’s won the award in this field.
— Yes. He ______ his maximum potential in the past decade.
— Yes. He ______ his maximum potential in the past decade.
A：explored
B：is exploring
C：has been exploring
D：has explored
答案(点此获取答案解析）
C
，
，
的斜率分别为
，
，
，则( )