1、提高GMAT作文水平，首先要分析原因
原因上的问题，有以下三个：
可疑调查
样本不足
结论无据
2、提高GMAT作文水平，也离不开分析结果
结论上的问题，有以下两个：
无因果联系
二者择一
3、提高GMAT作文水平更需要论证上的分析
就是论证过程上的问题，有以下两个，纵向横向各一个：
错误类比
时地全等
这样，只要记住了三字诀：因、果、证，就很容易记牢全部GMAT作文的问题了。为了进一步夯实GMAT作文的记忆方法，我们下面讲解一篇案例
下面是往期的一篇GMAT作文：
Our total sales have increased this year by 20 percent since we added a pharmacy section to our grocery store. Clearly, the customers main concern is the convenience afforded by one-stop shopping. // 无因果联系，可能另有他因。 The surest way to increase our profits over the next couple of years, therefore, is to add a clothing department along with an automotive supplies and repair shop. We should also plan to continue adding new departments and services, such as a restaurant and a garden shop, in subsequent years. // 时地全等 Being the only store in the area that offers such a range of services will give us a competitive advantage over other local stores. // 结论无据