I turned to the headmaster and he promised to do everything _ his power to help. me out.A.

问题补充：

I turned to the headmaster and he promised to do everything _ his power to help. me out.

A. beyond

B. above

C. under

D. within

答案：

A. beyond

B. above

C. under

(答案→)D. within

解析：考查介词，beyond 超出范围，above 在什么上面，under 在什么下面，within 在什么范围之内，句意：我向校长去求助他答应在他的权利范围之内，他会尽力帮助我。所以选D。