[第12章电子信息类专业英语第二版课本李白萍.ppt

　　[3]? The rapid evolution of LANs and metropolitan area network (MANs) to high speeds, efficient inter-working, and wider availability, together with advances in software control, is making possible most of the services currently envisioned as supported by ISDN and others beyond the capabilities of narrowband ISDN.　　局域网和城域网在向高速、高效互连和更广泛应用方面飞速发展，并且与先进的软件控制相结合，使当前大多数业务通过ISDN和窄带ISDN之外的其他技术的支持正在成为可能。　　· 本句的主句结构为The rapid evolution…，is making possible…。as supported by…为条件状语。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 　　[4]? It is essential that ISDN, if it is to achieve the ubiquity needed for low cost, inter-work with these alternative architectures and exist within them as “virtual ISDN” when appropriate.　　如果是为了普遍满足低价的需要，那么ISDN的实质应该是与不同结构的网络相连，并在恰当的时候作为这些网络的“虚拟ISDN”存在。　　· 逻辑上的主语是ISDN inter-work…and exist…，中间插入if it…是条件状语从句。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 　　[5]? In particular, it has to be possible to provide extension telephone service on the same channel as it exists in homes today, to communicate between an ISDN telephone and a PSTN telephone, and to send data between an ISDN terminal, with its direct digital connection to the ISDN, and a terminal-modem combination communicating data through a PSTN voice channel.　　特别的是，目前家庭使用的同一信道上提供扩展的电话业务，在ISDN电话和PSTN电话之间进行通信，在直接用数字连接的ISDN终端与通过PSTN话音信道进行数据通信的终端——调制解调器组合之间传达数据应该是可能的。　　· 本句是一长句，to be possible有三个并列成分：to provide…，to communicate…，and to send。　　· ISDN terminal和terminal-modem combination分别用插入语和分词短语修饰。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. EXERCISES 1.? Fill in the blanks. 　　(1) ?The most difficult applications to develop ISDN services are and . 　　(2) ?Smart building will contain , , , and . 　　(3) ?ISDN services include ,