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问题 单项选择题

下列关于 PowerDesigner 的叙述中，正确的是______。

A．只能在概念层上建立和维护数据模型

B．只能在物理（逻辑）层上建立和维护数据模型

C．既能在概念层上也能在物理层上建立和维护数据模型

D．既不能在概念层上也不能在物理层上建立和维护数据模型

答案

参考答案：C

解析：PowerDesigner DataArchitect用于两层的即概念层和物理层数据库设计和数据库构造。DataArchitect 提供概念数据模型设计，自动的物理数据模型生成，针对多种数据库管理系统（DBMS）的数据库生成， 开发工具的支持和高质量的文档特性。使用其逆向工程能力，设计人员可以得到一个数据库结构的“蓝图” 可用于文档和维护数据库或移植到一个不同的DBMS。

单项选择题

Lichens may grow on the bark of a tree in a steaming tropical rain forest, on the bricks of big city buildings, on rocks in hot springs, on wind-swept mountaintops, and in the driest desserts. In the arctic, they provide the principal food for caribou, and they are one of the few plants that grow in Antarctica. They are pioneers, appearing in barren rocky areas and starting the formation of soil in which mosses, then ferns, and then other plants can take root.
Lichens are a partnership of two plants — fungi and algae. The lichen body is made up of a network of fungal strands. In the upper layers of these grow groups of algae. The two organisms live together to the benefit of both, a relationship known as symbiosis. The fungi provide support, absorb water, and shelter the tender algae from direct sunlight. The algae carry on photosynthesis and provide the fungi with food. The algae can live independently and are recognizable as a species that grows alone. The fungi, on the other hand, cannot live apart from their partners. They can be placed in known classes of fungi but are unlike any species that lives independently.
So definite are the form, color, and characteristics of these double organisms that for hundreds of years, they were classified as one. More than 15,000 "species" were named. If these organisms are classified as separate species, it is difficult to fit them into the existing system of classification. But if they are classified separately, these species of fungi seem rather strange. Lichens are a splendid example of the difficulties faced by taxonomists in classifying species.

The word "splendid" underlined in Paragraph 3 most probably means ______ .

A．unique
B．improbable
C．excellent
D．famous
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单项选择题

内部专卖管理监督的原则不包括（）。

A.依法行政的原则

B.公平、公正的原则

C.全过程监管的原则

D.属地管理的原则
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