伏安法测电阻的原理是____ ,其方法是用____ 测出待测电阻两端的电压,用____ 测出通过待测电阻的电流,再计算待测电阻的阻值.
Fred ________ many football boots. But this pair of boots ________ the nicest.
中国古代帝王中废行省、设三司;废丞相、权分六部的是( )