Question

Yes,it+was+the+doctor+told+him变为被动语态？

Answer 1

Yes, it was the doctor who told him. 是的。是医生告诉他的。
这是一个强调句型的句子，句中对主语The doctor 强调，如变为被动语态，则要改为对宾语强调，即对 him强调，且同时将 him(宾格)改为he(主格)，最后根据原句是一般过去时将 told 改为被动结构 was told, 句末可加上介词by短语: by the doctor。
正确答案如下: Yes,it was he who was told by the doctor. 是的，是他被医生告之的。

Answer 2

变为被动语态：
Yes, indeed he was told by the doctor.

Answer 3

He was told by doctor