A：宗法制的衰落
B：分封制的瓦解
C：郡县制的实施
D：世官制的沿袭
---It's everyone's duty to join the Clean Your Plate Compaign(光盘行动).
---Sure, we should try to all the food that we have ordered.
在盛有KI溶液的试管中，滴入适量氯水充分反应后，再加四氯化碳振荡，静置后观察到的现象是( )
