Some people will be facing a big ______ if they do not have enough money when they get older.

A、society
B、population
C、challenge
出自:国家开放大学网络实用技术基础

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
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