记叙事情发生、发展或变化过程时，通常应当按照时间的先后将该事情发生、发展或变化过程分为几个阶段，提炼每个阶段的内容、特征和意义。然后，以一个概述性的句子为开始，逐一进行记叙。概述性的句子应该表示记叙该事情发生、发展或变化的目的或意义，它是记叙事情的核心内容和意义，也是记叙文段落的中心句或主题句，后面的记叙应当紧紧围绕这一核心，逐步展开其具体的记叙内容。例如：

Mobile phones have changed greatly since they were invented. The first generation of mobile phones could only be used to make phone calls. Since the technical support was not mature at that moment, the signal of the first generation mobile phones was not stable. Because the first generation mobile phones were big and heavy, they were not very portable. The second generation, widely used during the 1990s, could be used to make phone calls and send text messages. Compared to the first generation, the second generation mobile phones had more stable signal and became more portable. With the development of technology, the third generation of mobile phones, the smart phones, differ greatly from those of the first and second generations. In addition to making phone calls and sending texts, the smart phones can also be used as a laptop/personal computer. People can also download different apps to their mobile phones, such as games, WeChat, Alipay and so on. It is common to see people use smart phones to build up their social network, pay bills, and shop online. The smart phones really have become an important part of people's life.

首先，中心句“Mobile phones have changed greatly since they were invented.”作为短文的第一句，紧接其后的是手机发展的三个阶段，即：“The first generation...could only be used to make phone calls.”“The second generation, widely used during the 1990s, could be used to make phone calls and send text messages.”和“With the development of technology, the third generation of mobile phones, the smart phones, differ greatly from those of the first and second generations.”。最后，总结这三个阶段在功能方面的特点，即：第一阶段仅能打电话，第二阶段能发短信和打电话，第三阶段的功能类似电话和笔记本电脑的综合。由此可见，短文中心突出，记叙的内容层次分明，结构严谨，通俗易懂。由于记叙文通常是记叙过去事情的发生、发展或变化，所以其谓语动词通常应当使用过去时。当然，可以根据过去事情的发生、发展或变化的进程和特点，使用过去将来时或过去完成时。