六、多变句式原则
1 加法（串联）
考生都希望写下很长的句子，像个老外似的，可就是怕写错，怎么办？最保险的方法就是在任何两个句子之间加and，但最好是前后两句句子有先后关系或者并列关系。比如说：I enjoy music and he is fond of playing guitar.如果二者并列，我们可以用一个超级句式，如：Not only the fur coat is soft，but it is also warm.其他的连接性短语可以用：besides，furthermore，likewise，moreover等。
2 转折（拐弯抹角）
批评某人缺点的时候，我们总习惯先拐弯抹角说说他的优点，然后转入正题，再说缺点。这种方式虽然狡猾了点儿，可毕竟还比较容易让人接受。所以呢，我们说话的时候，也可以在要点之前先来点儿废话，再使用转折关联词，来个180度大转弯。例如：
The car was quite old，yet it was in excellent condition.
The coat was thin，but it was warm.
其他表示转折的短语：despite（that），still，however，nevertheless，in spite of，notwithstanding。
考博作文以论说文为主。论说文写作要求“四化”：语言准确化，词句多样化，结构清晰化，内容简单化。
1.语言准确化
语言准确化主要表现在词汇准确和造句准确上。
词汇准确化主要体现于以下四个方面：1）拼写；2）介词；3）同义词；4）正规和非正规。
句子准确化主要是避免写病句。考生常见的错误有：1）主谓不一致；2）逗号滥用；3）重复；4）逻辑主语和主句主语不一致；5）修饰语位置乱放；6）不分可数名词与不可数名词；7）冠词乱用；8）句子不完整；9）词语误搭配；10）句子无主语；11）一个句子有几个谓语动词；12）中国式英语。
2.词句多样化
词的多样化是指用词要多样。比如说图表作文，我们会用到show，但也可以说reveal，indicate，illustrate等。再比如“认为”，我们可以说think，也可以说hold，maintain，insist。表达“越来越”不要总说more and more，还可以用in growing numbers，on the rise等。
句子的多样化主要在几个方面：句子开头多样化，主语多样化，定语多样化，长短句变化。比如，大部分考生都喜欢用“主谓宾”砖头式的句子，不知道变通一下，用不定式、形容词、介词短语、分词、同位语或从句开头。使用句子还要讲究平行原则，如何把短句连接或扩展成为长句。(https://www.daowen.com)
3.结构清晰化
结构清晰化就是要求考生最好把主题句写在段首。另外，句子与句子之间要注意过渡词的使用。分析原因或者列举段落我们提倡“条理原则”，即要经常说“首先，其次，然后，最后”。比如，首先：to begin/start with，first and foremost，most important of all；其次：then，furthermore，moreover，what’s more，in addition，besides；最后：last but not least，finally。如果是讲两种人或两种情况，可以说on the one hand，on the other hand或for one thing，for another。
4.内容简单化
考博作文题型存在的主要目的，是为了考查考生的英语语言表达能力，而不是考查是否有构思能力、编剧能力。切记不用把内容想得多么复杂，复杂内容的英文表达会更难。退一步说，就算让考生当场写一篇字数在160～200个字左右的短篇汉语文章，他们也不一定能写出什么惊天动地、见解独到的微型杂文来。所以考生只要举一些简单常见的例子就行了。
每日训练
Directions:Read the following paragraph and then write a response paper of about250 to 300 words.
Quite a few teachers complain about students reading fewer books than before.In fact，students nowadays spend more time surfing on the Internet and watching movies on DVD's.Naturally they spend less time reading books.Do you think that students today are less knowledgeable because they read fewer books？
参考范文
There is a frequent complaint among teachers today that students read fewer booksthan before and that they are less knowledgeable as a result.At first sight，this argument seems reasonable.However，a careful inspection at it reveals how flimsy it is.In my view，students today are generally more knowledgeable than the elder generations.
Truly，students now spend less time reading paper books，but they spend more time surfing the Internet and watching movies on DVDs.It is，as I see it，just a change in the means of acquiring knowledge.
Actually，there is a far larger amount of information on the Internet than contained by traditional books.On the Internet you can not only be provided with the most detailed and latest reports on what is happening around the world，but can also learn about the history of an event by linking to related web pages.Besides，the so-called e-books are not a bit inferior to paper books either in amount or in content.A lot of classical works can now be read online.Last but not least，thanks to the net，students today can communicate with people in almost any corner of the world，which can considerably expand their horizons and enrich their knowledge.
DVDs are another important means for young people today to master knowledge.Compared with paper books，this new kind of device is far more vivid and alive.Besides，almost all information in traditional books can be conveyed in the form of DVD classical novels can be made into movies and played，poems can be read aloud and accompanied by pictures，and even courses in school can be made into videos.
To sum up，reading fewer books by no means render modern students less knowledgeable.Instead，they are exposed to a lot more knowledge than previous generations.