教学过程中常常遇到一些备考雅思的同学，他们有着不错的雅思语言功底，词汇量丰富，语法上看不会出现什么问题，还常常出现长难句。但他们的雅思写作分数常常不尽人意。面对这些千年6.5的考生，深究其中的原因，往往不外乎，写作中论证的质量和逻辑没有达到要求。这一类学生，6.5分证明了他们不错的语言实力;但跨过6.5分的坎儿则要求的是逻辑推理和论证能力。
首先，我们来看一下雅思写作的四项评分标准：
1. Task Response
2. Coherence & Cohesion
3. Lexical resource
4. Grammatical range & accuracy
刚才所提到的这类考生，自然是在3和4两方面能拿到较好的分数，但对于1和2的要求却并没有深入了解，而这两项评分也正是正文段的逻辑要求即论证的充分性和完备性。那1和2具体要求什么呢?其实就是从不同的方面具体地讨论话题，做到deeper and wider，而6.5以下的作文则是把话题想得过于简单，只是泛泛而谈。
接下来我们分析实例， 一篇一对一学生的课堂练习
题目：有人认为保护濒危灭绝动物纯属浪费时间和大量金钱。你同意吗?
学生正文段写反对的论点，一共有三个：
(论点1):Maintaining lives of these dying-out animals is far from describing the significance of existence of them. The value of using extractions from wild lives for research and development is immeasurable, so keeping biological diversity is a necessity for further exploration of advanced medicines in pharmaceutical area.(论点2)Moreover, permanent disappearance of certain species has the risk of breaking equilibrium of ecosystem. Once one of links of food chain is destroyed, the consequence afterwards is disastrous and irreversible.(论点3)In addition, since interference and invasion into animal’s habitats by human beings is the arch-criminal of extinctions of endangered species, humankind has obligation to do something o fix their faults.
在这篇作文中，学生一共列举出来三个理由反对题目的观点，即动物本身价值，破坏生态平衡以及人类行为导致他们灭绝。学生一般都会有这种错觉，觉得论点越多，思路就显得越广，因此文章必定不错。但这个片段并没有对每一个论点给出具体的论证，从形式看是“句句在理”，而从内容来看则是“空洞乏力”。那怎么样才算是论证充分呢?
我们来看下面的片段：
It is vital that we appreciate the importance of endangered species in maintaining the balance of nature. (首句提出反驳题目的观点)Ecosystems are delicate arrangements where plants and animals all depend on each other for survival. (对于生态系统给出具体解释)The disappearance or introduction of any animal species disrupts the balance and negatively impacts upon other plants and animals by breaking the food chain and altering the habitat in which they live. (给出假设：物种的引进和灭绝都会破坏平衡)Such imbalances frequently return to haunt us in unexpected ways. (阐述其结果：危害人类生存)Just as rabbits that were introduced to Australian soon after European settlement now compete with native species for food and destroy farmers’ crops, the extinction of a predator can cause plagues by allowing its prey to multiply unchecked. (举出实例：兔子带来的结果)Therefore, since endangered ecological change constitutes a potential risk to us and our environment, it is clearly in our own interests to protect endangered species. (回溯观点：威胁人类生存，保护濒危动物刻不容缓)
通过对比，我们会发现两个版本虽然都阐述应该保护此类动物，但是很明显学生的片段则把重点放在论点的量，即三个方面;而第二个版本侧重于论证的质，即如何论证充分让其环环相扣。那到底哪个才接近7分以上作文的标准呢?当然是后者。
为了让大家能够更清楚地感受这种论证地充分性，再来看另一个话题：抽烟危害健康，为了公众的健康，应该禁止抽烟。你怎么看?

对于这个题目，经常有学生这么想，很想写同意，但会发现同意的部分对于“危害健康”这个点实在难以做到写的具体实在，几句空话一讲便没了下文。那到底该怎么论证?
我们来看范文的片段：
Perhaps the strongest argument in favor of banning cigarettes and other tobacco products is that of public health. (首句概括主旨) It is an irrefutable fact that smoking leads to lung cancer and other such as potentially fatal diseases. (给出解释：抽烟导致癌症和其他疾病)Pro-smoking groups would no doubt agree that each individual has the right to determine what goes into his or her body. (让步观点：反对禁止抽烟者觉得这是他们的自由)Nevertheless, I would suggest that the interests and rights of society at large, must override those of the individual. (以退为进：必须看重大局利益)The medical treatment that smokers require is often incredibly costly, and it is frequently governments and society that cover these costs rather than the individual smoker. (给出另一个理由：香烟带来疾病，而疾病需要大量费用医治)Hence, laws prohibiting smoking would be entirely justified. (回溯观点：禁止抽烟合理性)
通过上述的内容，相信大家对于论证充分和具体的概念有一定的理解。在备考阶段对于每一个话题进行background research 准备大量论据之后，是时候去思考如何将自己的正文片段写得具体充分而避免泛泛而谈，而这也是跨过6.5迈向7分的重要途径。