A state of emergency had been in force since the emperor was overthrown .
【正确答案】 C
【答案解析】解析:C项overturn“毁灭,颠覆”和overthrown“颠覆”为同义词。其他选项分别为:overtake“赶上,超过”,overrun“泛滥,侵占”和overdrawn“透支”。