Is your father a worker ? No but he .A.used to do B.used to be C.is used to be

问题补充：

Is your father a worker ? No，but he .

A.used to do B.used to be C.is used to be

答案：

解析：句意：你的父亲是工人吗?不是，但他以前是。used to do ,过去常常做某事，故选B。