2. 句型及常用表达结构：
举例：
There are many examples to prove… Here I will cite just a few.
There is enough/convincing /sufficient evidence to prove that…
Just take …as an example.
The case effectively clarifies the fact that …
Though numerous examples can be given, this/these will be sufficient.
因果：
There are several reasons for…
The reason why …can be traced to…
The causes for …are as follows…
Therefore, we can draw/arrive at/reach/make the following conclusion…
There are many causes/reasons for…. Firstly, …, secondly, …, thirdly,…
…also contribute to the reason why…
分类：
…may be classified according to /on the basis of /depending on…
…may be divided into…
(三)转
转折：
but, however, yet, instead, whereas, otherwise, nevertheless, unfortunately
They may be right about …, but they seem to neglect the fact that…
对比：
just as, in comparison, like, similarly, likewise, correspondingly, similar to, in contrast, on the other hand, on the contrary, unlike
There are some similarities/differences between…
We can compare …with …
…has something in common with…
By contrasting …and…
…has little common with…
Although it is widely accepted that …, it is unlikely to be true that…