WHO建议，按照60岁以上老年人口系数达到多少百位比为老年型社会（）
A.5％
B.10％
C.15％
D.20％
E.25％
参考答案：B
I()have watched that movie--it'll give me horrible dreams.
A. shouldn' t
B. needn' t
C. couldn't
D. mustn't
《孔雀东南飞》在叙事诗发展史上有何意义？
