—Where does he come from?—I know nothing about him except that he is a doctor occupation.A

问题补充：

—Where does he come from?

—I know nothing about him except that he is a doctor occupation.

A. in

B. by

C. through

D. for

答案：

A. in

(答案→)B. by

C. through

D. for

解析：考查介词：by occupation职业的，句意：他从哪里来？--我对他一无所知，除了他是个医生。选B。