不可撤销保兑的信用证项下的汇票，经保兑行付款后，如开证行因故拒绝，保兑行可以向受益人追索款项。
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?（） [" Create one FindCriteria object for each interface and set the Duration of each FindCriteria to 30 seconds. Call the FindAsync method of the DiscoveryClient class twice, one time for each of the FindCriteria objects, to search for the services."," Create one FindCriteria object for each interface and set the Duration of each FindCnteria to two seconds. Create a loop that calls the Find method of the DiscoveryClient class to search for the services. Within each loop iteration, call the Find method of the DiscoveryClient class once for each of the FindCriteria objects. Run the loop until a service is found or 30 seconds pass."," Create a single FindCriteria object and add both interfaces to its ContractTypeNames collection. Set the criteria's Duration to two seconds. Create a loop that calls the Find method of the DiscoveryClient class to search for the services. Within each loop iteration, call the Find method of the DiscoveryClient class to search for the services Run the loop until a service is found or 30 seconds pass."," Create a single FindCritera object and add both interfaces to the ContractTypeNames collection. Set the Duration to 30 seconds and use the FindAsync method of the DiscoveryClient class to search for the services."]
婴儿语言发展四个阶段的正确表述是（）。 ["单字句，电报句，简单句，复合句","单字句，多字句，简单句，复杂句","复合句，单字句，电报句，简单句","单字句，电报句，复合句，简单句"]
桩身出现水平整合型裂缝或断裂，竖向抗压承载能力可能满足设计要求，但存在哪方面的隐患。（） ["水平承载力不满足要求","不能支撑上部结构传递的荷载","耐久性","桩周土受压时宜破坏","混凝土强度不够"]
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?（） [" AnnouncementService"," AnnouncementClient"," DiscoveryClient"," HttpListener"]
简述古代希腊早期僭主政治。
