当x=-2时，代数式x2+2x+1的值等于______．

What is logistics? In the current business environment,logistics is generally accepted as a very important element for the economic development and business growth of a region,especially a port city. In reality,what does logistics mean?In which way does it operate? For simple definition,logistics is a set of procedures in which commodity is delivered in an efficient manner from suppliers to customers.There are three key aspects to the concepts: 1．Movement of goods Goods can be considered as valuable objects,such as cargo and materials that are valua-ble and purchasable through commercial transactions and processes.Flow can be determined as methods in which goods are moved or transferred between locations,intermediaries and merchandisers.Modes of transportation include motor,rail,water,air and pipeline. 2.Direction of the flow of goods In the open market place,buyers and sellers represent two ends of a commercialtrans-action.Buyers are usually customers who demand the goods,while,as sellers are suppliers who provide such goods.When a transaction is agreed upon (sometimes payment is comple-ted,other times the payment is arranged to be completed at a later stage),the suppliers have the responsibility to arrange for the goods to be delivered to the customers. 3.Efficient management of the flow process The transportation of goods should bear low cost and ensure safety and punctuality.It should do its best to avoid wasting customers＇resources.Currently,the flow of goods is generally controlled by both hardware and software.By hardware,we mean logistics facili-ties and equipment,such as ports,warehouses and trucks,ships,railroad,cars and air-lines.By software,we mean information system,standardization and data sharing.Questions:

Which of the following is a key aspect of logistics？（）

A.Goods.

B.Customers.

C.Suppliers.

D.Movement of goods.

数据库三级模式体系结构的划分，有利于保持数据库的 ______ 。

A．数据独立性

B．数据安全性

C．结构规范化

D．操作可行性

在VisualFoxPro中，对未经排序或索引的数据库进行查找时，只能用命令（）。

A、find

B、seek

C、locate

D、display

下面表示11城市指数的公式( )是正确的。

A．S₁₁=P₁/(P₂+P₃+…+P₁₁)
B．S₁₁=P₁/(P₂+P₃+…+P₁₀)
C．S₁₁=2P₁/(P₂+P₃+…+P₁₁)
D．S₁₁=2P₁/(P₂+P₃+…+P₁₀)

简述盗窃银行案件的特点？