单项选择题 A Windows Communication Foundation (WCF) service sends notifications when the service is started and stopped.You need to implement a client that logs these notifications. Which class should you use?（）

单项选择题 You are implementing a Windows Communication Foundation (WCF) client application that consumes the ICatalog and lCatalog2 service interfaces.You need to ensure that the client discovers services implementing these interfaces. The services may already be online or may come online within a 30 second time limit. How should you use WCF Discovery to accomplish this?（）

单项选择题 An ASP.NET application hosts a RESTful Windows Communication Foundation (WCF) service at /Services/Contoso.svc.The service provides a JavaScript resource to clients. You have an explicit reference to the JavaScript in your page markup as follows.You need to retrieve the debug version of the service JavaScript. What should you do?（）