--- Jack, did you happen to see ____ black and ____ white cat?

--- Is she missing? I told you to take care of her.

A．the; the 　　　

B．the; /　　　

C．a; / 　　　

D．a; the

加聚反应是指单体经过加成聚合反应所的产物叫做加聚物，加聚物的元素组成与其单体相同，只是电子结构有所改变。