1.描述过程，流程常用句子
the following diagraph shows the structure of……
the picture illustrates……
it mainly consists of……
it works as follows.
it always involves following steps.
the whole procedure can be divided into…stages. 

2.描述流程，过程的常用过渡性词语
firstly
secondly¹
thirdly/finally

the first step is to
the next step is to
the last step is to

the first stage involves
in the next stage
in the following stage
in the last stage

first of all
to begin with
next
then
later
at the same time
simultaneously²
subsequently
consequently
before this
during
after this

in the course of
in order to/in order not to
in order that
so as to/so as not to

描述流程的文章，应说明：
1． 首先说明是做什么工作的过程，目的是什么
2． 准备工作
3． 按时间/过程先后描述
4． 结果
5． 简单总结（可有可无）

描述一个实物/器具的工作过程，文章应分以下几点：
1． 实物是什么，做什么用的
2． 基本结构
3． 工作过程
4． 简单总结