正确

错误

正确

错误

水平分割后，得到的子表结构相同

水平分割后，查询表中所有数据时需要使用JOIN操作

垂直分割后，所有表中均需保留原有表的主码

当查询表中所有数据时，使用分割表方法会增加查询表达式的复杂度

正确

错误

dramatic

acquiring

recall

neighborhoods

boosting

laid low

passed through

stepped up I hang around J. move out Can you 1 a time when the area where you live was very different from what it is today? Given the 2 changes that China has 3 in recent years, that would not be surprising. Whole 4 have been transformed. New construction has meant that the housing stock has improved in size and quality. As a result of redevelopment many people have been able to 5 of old housing into new accommodation that offers better amenities, 6 their standard of living. This is naturally to be welcomed, but the change has not been without some costs. As whole areas of traditional low-rise housing have been 7 to make way for high-rise apartments, opportunities for neighbors to casually 8 with each other have frequently declined.

30%，70%

15%，85%

40%，60%

20%，80%