[填空题] 数据模型的规范化可提高数据的（）、（）、（）

You work as an application developer at Certkiller .com. You are currently in the process of creating a class that stores data about Certkiller .com’s customers. Certkiller .com customers are assigned unique identifiers and various characteristics that may include aliases， shipping instructions， and sales comments. These characteristics can change in both size and data type. You start by defining the Customer class as shown below： public class Customer { private int custID； private ArrayList attributes； public int CustomerID { get {return custID；} } public Customer （int CustomerID） { this.custID = CustomerID； this.attributes = new ArrayList （）； } public void AddAttribute （object att） {  attributes.Add （att）； } } You have to create the FindAttribute method for locating attributes in Customer objects no matter what the data type is.You need to ensure that the FindAttributemethod returns the attribute if found，and you also need to ensure type-safety when returning the attribute.What should you do？（） [" Use the following code to declare the FindAttribute method： public T FindAttribute （T att） {\/\/Find attribute and return the value }"," Use the following code to declare the FindAttribute method： public object FindAttribute （object att） {\/\/Find attribute and return the value }"," Use the following code to declare the FindAttribute method： public T FindAttribute  （T att） {\/\/Find attribute and return the value }"," Use the following code to declare the FindAttribute method： public string FindAttribute （string att） {\/\/Find attribute and return the value }<\/t>"] 投资回收期法的主要优点有（）。 ["考虑了资金的时间价值","使用简单、方便","在一定意义上考虑了投资风险因素","投资回收期的经济意义易于理解"] 生物进化主要是基于（）的相互作用。 ["生物代际之间","生物种群之间","生物与其环境","生物内部个体"] You are implementing a new Dynamic Data Web site. The Web site includes a Web page that has an ObjectDataSource control named ObjectDataSource1. ObjectDataSource1 interacts with a Web service that exposes methods for listing and editing instances of a class named Product. You add a GridView control named GridView1 to the page， and you specify that GridView1 should use ObjectDataSource1 as its data source. You then configure GridView1 to auto-generate fields and to enable editing. You need to add Dynamic Data behavior to GridView1. You also must ensure that users can use GridView1 to update Product instances. Which two actions should you perform？（） ["Add a DynamicDataManager control to the Web page.","Disable the auto-generated fields on GridView1. Add a DynamicField control for each field of the Product class.","Add the following code segment to the Application_Start method in the Global.asax.cs file.","Add the following code segment to the Page_Init method of the Web page."] 保留金的最高限额一般为合同总价的（）。 ["4%","5%","10%","15%"] 数据模型的规范化可提高数据的（）、（）、（）