数据模型分为格式化模型与非格式化模型，层次模型与网状模型属于______。
参考答案：格式化模型
解析： 层次模型与网状模型属于格式化模型。
History is the best teacher. It _______records the development path of each country and foretells the future to us.
A．apparently
B．conventionally
C．faithfully
D．eventually
