卫生改革以效率为主，兼顾公平

A．The empire was ruled under the local administrative system of commandery and prefecture.
B．Confucianism became the official state ideology.
C．The currency was standardized to the Ban liang coin.
D．The Chinese script was unified.

A．每年一次；每年一次。
B．每年两次；每年一次。
C． 每年一次；每5年一次。
D． 每年一次；每年两次。