What experience does the man have that may be helpful？A．He knows how to operate the gradin

What experience does the man have that may be helpful？

A．He knows how to operate the grading machine.

B．He has answered the telephone in a law office.

C．He has used computer programs for office work.

D．He has been a work-study student in another office.

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！