will do good to a senior student to do a part-time job when she wants to know more about s

问题补充：

will do good to a senior student to do a part-time job when she wants to know more about society

A. As

B. It

C. That

D. He

答案：

A. As

(答案→)B. It

C. That

D. He

解析：考查it做形式主语，句意：当高中生想了解社会的时候，做兼职工作对他是有好处的，it指代to do a part-time job，选B。