四川邮电职业技术学院教案专用纸 a checksum. Packets are transmitted independently in a store-and-forward man III. While-reading Activities i New words and phrases Students read the new words and phrases aloud one by one after teacher. 3 minutes) l1. lext organIzation 1. Ss read the text and point out the main idea of the text. The main idea The text mainly discusses the trait of C ircuit Switching and Packet 15 mins 2. Ss make an analysis of the organization of the text The text may be divided into four major sections Sectionl(Lines 1-12): the principle of Circuit Switching Section2 (Lines 13-35): the principle of Packet Switching Section3Lines 36-76): the predominance of Packet Switching iii. Key language points 本篇课文涉及到交换领域,题目 circuit switch ing and packet switching可译为“电路交换与|4sms 分组交换 2. In circuit switching, a total path of connected lines is set up from the origin to the destination at the time the call is made, and the path remains allocated to the source-destination pair( whether used or not)until it is released by the communicating parties在电路交换中,当呼叫发生时,由 呼叫源点到终点之间要建立整个通路的连线,而且在通信双方释放该电路之前,此通路 直保持分配给这对源点一终点(不管通路是否使用)。本句中的 the call is made是一个定语从 句,修饰 the time,可译成呼叫(被作出)的时候 allocated系过去分词,在句中作形容词用 3. The switches, called circuit switches (or office exchange in telephone jargon ), have no capability of storing or manipulating users data on their way to the destination.被称为电路交 换机(或以电话行业用语称之为局交换)的交换设备没有存储或控制用户送往终点路由数据 的能力。句中的 storing和 manipulating均为动名词形式, users data系它们的动词宾语 4. The circuit is set up by a special signaling message that finds its way through the network, seizing channels in the path as it proceeds.电路由特殊的信令建立,该信令通过网络选择路 由,并在其进程中确定信道。句中的 seizing为现在分词,它作为动词fnds的伴随情况 5. In message switching, the transmission unit is a well-defined block of data called a messa In addition to the text to be transmitted, a message comprises a header and a checksum. iEf&x 交换中,传输单元是一个被精心定义的数据块,该数据块称为报文。 to be transmitted为动 词不定式的被动态,修饰text,可译成要传的内容 Page 3 of 5 Teaching Plan of English for Telecommunications四川邮电职业技术学院教案专用纸 Page 3 of 5 Teaching Plan of English for Telecommunications Unit11 a checksum. Packets are transmitted independently in a store-and-forward manner III. While-reading Activities i. New words and phrases Students read the new words and phrases aloud one by one after teacher.( 3 minutes) ii. Text organization 1. Ss read the text and point out the main idea of the text. The main idea: The text mainly discusses the trait of Circuit Switching and Packet Switching 2. Ss make an analysis of the organization of the text . The text may be divided into four major sections. Section1 (Lines1-12): the principle of Circuit Switching; Section2 (Lines13-35): the principle of Packet Switching Section3(Lines36-76): the predominance of Packet Switching iii. Key language points 1.本篇课文涉及到交换领域，题目 circuit switching and packet switching 可译为:“电路交换与 分组交换”. 2. In circuit switching, a total path of connected lines is set up from the origin to the destination at the time the call is made, and the path remains allocated to the source-destination pair (whether used or not) until it is released by the communicating parties 在电路交换中，当呼叫发生时，由 呼叫源点到终点之间要建立整个通路的连线，而且在通信双方释放该电路之前，此通路一 直保持分配给这对源点一终点(不管通路是否使用)。本句中的 the call is made 是一个定语从 句，修饰 the time，可译成:呼叫(被作出)的时候.allocated 系过去分词，在句中作形容词用. 3. The switches, called circuit switches (or office exchange in telephone jargon), have no capability of storing or manipulating user's data on their way to the destination. 被称为电路交 换机(或以电话行业用语称之为局交换)的交换设备没有存储或控制用户送往终点路由数据 的能力。句中的 storing 和 manipulating 均为动名词形式，user's data 系它们的动词宾语. 4. The circuit is set up by a special signaling message that finds its way through the network, seizing channels in the path as it proceeds. 电路由特殊的信令建立，该信令通过网络选择路 由，并在其进程中确定信道。句中的 seizing 为现在分词，它作为动词 finds 的伴随情况. 5. In message switching, the transmission unit is a well-defined block of data called a message. In addition to the text to be transmitted, a message comprises a header and a checksum. 在报文 交换中，传输单元是一个被精心定义的数据块，该数据块称为报文。to be transmitted 为动 词不定式的被动态，修饰 text，可译成:要传的内容. 3 mins 15 mins 45mins