与地垒有关且在其两侧的断层总是（）。
A、性质不同
B、性质相同，倾向相反
C、性质相同，倾向相同
D、逆断层
参考答案：B
已知有一个关键字序列为(99,38,309,08,27,145,67,96,186,122,71,63,59)，假设用散列函数为h(key)=key%13，现在如果采用拉链法解决冲突问题，请画出这组关键字的散列表。
Declaration documents, import and export documents, contracts and other data directly related to import and export transactions shall be retained for ______ effective from the date of release of import and export goods.
A. one year B. two years C. three years D. four years
