在数据库的三级模式结构中，内模式有______个。
参考答案：A
根据中文提示完成下列句子。
1. What is your ___________ (地址)?
2. There are ___________ (很多) shops in the city.
3. Sometimes I ___________ (想念) my mother.
4. Don't ___________ (忘记) the stamp.
5. I go to Canada in ___________ (二月).
As we all know，tigers and cats________the same family of beasts.
A．belonged to
B．are belonged to
C．belong to
D．are belonging to
