本文来自新航道重庆学校托福教研组老师。这一期托福备考干货我们继续探讨托福写作TASK 2的学术写作，上次讨论了如何利用例证链去展开初步的论证，这次我们来看一下如何利用对比来加强说服力。以下面这个反复出现过的科技类考题为例：

　　Your professor is discussing sociology. Write a post responding to the professor’s question.

　　In your response you should:

　　• express and support your opinion

　　• make a contribution to the discussion

　　An effective response will contain at least 100 words. You will have 10 minutes to write it.

　　Doctor Achebe:

　　This week's course materials will focus on scientific discoveries. While scientific researchers usually prefer to share what they learn with other scientists, many businesses and governments keep certain scientific discoveries secret. Some people believe that all scientific discoveries should be shared freely among scientists all around the world and that governments and businesses should not keep any discoveries secret. What do you believe and why?

　　题干总述的关键词是share scientific discoveries。

　　代表题干关键信息的词是while scientific researchers…many businesses and governments以及some people believe that ….，提示学生要讨论的中心是：是否应当免费共享科研成果。题目要求大家提出自己的立场以及阐述原因。接下来看两位同学的观点：

　　Kelly:

　　I don't think all discoveries should be shared. Businesses, for example, often spend a lot of money on scientific research in order to make a discovery that can lead to profit. Even if that discovery benefits everyone, the business has a right to keep the discovery secret so that it can develop a profitable product from the research.

　　Paul:

　　Sharing knowledge is crucially important to most scientists. Scientists usually publish the details of their discoveries in scientific journals, which means that everyone can see what the scientists have accomplished. Being recognized as the person who made a discovery is the biggest reward for any scientist. When scientists keep their discoveries secret, they lose that recognition. That is very unsatisfying.

　　从标记加粗的词当中我们能看到，Kelly认为企业有权保留自己的研发成果去谋求更多的利益，没有必要共享自己付出了大量0取得的结果。而Paul则提到了大多数科学家不仅仅需要了解他人的科研成果，也需要以此来获取更多的认可，从而得到更大的成就感。

　　这道题的双方都不是很难论证，同学们可以自行选择，我们在这里选择去论证“为什么不应当共享科研成果”，可以用来开头的句子是：

　　My personal perspective is that scientific discoveries is not necessary to be shared to the world, which is by the side of Paul.

　　接下来我们可以尝试用对比论证的手法去展开细节，当然还是要有例证是最好的：

　　Take military research as an example. It usually comes at the cost of billions of dollars in research and experiments. Without confidential policies, the vulnerability of military capability in a country would be exposed and people in the nation are also put in danger.

　　从上面的段落中能看到，without引导的句子是为了论证“如果不保密，会怎样”，以此作为对比去论证科研成果保密的重要性，而后文可以进一步利用similarly去进行类似点的对比。

　　在进行不同点的对比时，我们可以用到的短语包括：

　　In/ by contrast,

　　On the contrary,

　　In comparison,

　　With sth, …; without sth, ….

　　表示让步的连词也可以体现对比感：

　　Admittedly, granted, indeed,

　　Albeit …

　　Despite / in spite of sth, …

　　Nevertheless, …

　　如果想要比较相似性，可以利用的连词涉及到：

　　Similarly, likewise,

　　In the same manner,

　　Correspondingly,

　　比如刚刚提到的类似例证对比：

　　Similarly, for businesses, they would inevitably take the disadvantages of competing with other enterprises if sharing a specific technique freely.

　　这样的话，我们能同时cover到国家和企业两个方面，能相对全面一些。

　　当然我们也不必要拘泥于某一种特定的论证方式，对比法常常会跟因果/例证/假设等结合使用，只要上下文能做到意义和逻辑衔接顺畅就好。

　　接下来同学们可以试着利用对比论证去尝试写下面这个题目：

　　Doctor Achebe:

　　This week, we'll be discussing the future of education. Let's focus now on the following viewpoint: it is no longer useful to spend many years pursuing a traditional, specialized university degree in a single field, such as communications or economics. Instead, it makes more sense for most people to complete several shorter certification programs and earn certificates in, for example, project management, computer programming, graphic design, and so on. Do you agree or disagree with this viewpoint? Why?