读一读，猜一猜。

      My name is Bob. My father and mother have (有) six children (孩子). Half (一半) are boys and half

are girls. How many brothers do I have? How many sisters do I have?

1. I have ____________ brothers.

2. I have ____________ sisters.

唐代著名诗人刘禹锡《金陵五题·乌衣巷》写道：“朱雀桥边野草花，乌衣巷口夕阳斜。旧时王谢堂前燕，飞人寻常百姓家。”王、谢都是东晋著名的士族，当年他们居住在乌衣巷。从刘禹锡的诗中可以看出

A．九品中正制的腐朽

B．士族的没落与消亡

C．九品中正制在历史上有过进步作用

D．士族对于保存中原文化有积极意义