高分文章要求句子结构、句子类型、句子及段落的长短要有变化，这样才能使文章富有节奏、生动、易理解。关于句子方面的内容在上一章已详述。这里只强调段落的变化。一般来讲，英语文章包括三大段，第一段和最后一段是开头和结尾段，篇幅较短，占全文的1/3左右，中间段是文章的主体段，篇幅较长，占全文的2/3左右。这样写出来的文章会错落有致，富有变化感。此外，主体段按照具体的分论点可以分成相应的自然段，一般由1-3个自然段组成，各段的长度可以大致相同，也可由短到长安排，即最后一自然段阐述或举例最详细。就文章长度不超过200字的大学英语四、六级考试作文而言，主体段一般写一段即可。
主题句确立后，还要注意说明、解释主题句的内容是否与主题相符。统一性要求作者清楚地表达段落的主题思想；只提供与主题相关的信息及实例，其他再有趣的例子也应该放弃不用。总之，一个段落只能有一个中心，段落中所有内容都必须围绕这一中心展开，给读者一种整体感。
下面我们以 How to Succeed in a Job Interview?(2001.1 CET-4 & CET-6) 范文的第二段为例进行说明：
There are many factors involved. According to psychologists, it depends more on the first impression you leave which is half a battle: how you look, how you sound and what you say are of great importance. In the first place, how you look makes up 55% of a first impression. This includes facial expressions, body language, and eye contact, as well as clothing and general appearance. Among those, clothing is the most important to show your respect to the interviewer and to leave the interviewer a good impression in the end. In the second place, how you sound makes up 38% of the first impression. This includes how fast or slowly, loudly or softly you speak. So make sure that you sound friendly, interested, confident and happy in answering any inquires in the interview. Finally, what you say counts for only 7% of the message. Therefore, attach more importance to your appearance and expressions rather than your words.
本段在内容上就具备了统一性。段落第一句表明下文要阐述影响面试成功的因素。第二句指出心理学家的观点，面试成功与否取决于三个方面即 how you look, how you sound 和 what you say。紧接着文章围绕这三点进行了详细的解释和说明。相反，如果段中加入面试途中发生的一件趣事就会使其中心内容显得杂乱无章。
