The TV sets made by our factory sell best, but 10 years ago no one could have guessed the place in the markets that they _______.

A．were having

B．had had

C．were to have

D．had

中心下料预焙槽对原材料氧化铝的物理性能要求实际中以氧化铝的（）和净化反应的吸附性为主，兼顾其它要求。