简短的句子更能强调句子的含义, 句子越长读者越难判断句中哪部分最重要。因此，单个从句的句子比含有多重从句的句子更有分量。在段落或章节的开头部分使用短句，这样可以突出主题的重要性，也可以确保一下就抓住读者的眼球，让他们专注于主题。

同样，相对于依附其他句子的从句，读者会赋予那些独立存在的句子（独立句）更多关注。因此，独立句比从属句有分量，而从属句又比短语有分量。

例1

a   Rheumatic fever is an autoimmune disease.

b   It is generally accepted in the field of medicine that rheumatic fever is an autoimmune disease.

        a中“Rheumatic fever is an autoimmune disease”独自出现，而b中却作为长句的一部分，显然前一种形式的表达更有力。

        科技论文的句子不需要太复杂。总的指导原则是，不要用一句话表述太多的含义。找出最重要的信息，只有确定了最重要的，才能依次确定次要的，然后省略掉不重要的。通常，可以考虑将次要信息剥离为独立的句子。

D 例 2  

Skin swabs were cultured at the time of the removal of the catheter from seven patients with catheter-related bloodstream infection and in five of these cases (71%), the culture yielded bacteria of the same species with a DNA fingerprint pattern similar to that of the isolates from the catheter and the blood, whereas a different organism grew from skin cultures in the other two patients (29%), suggesting that catheter infection may have originated from contamination of the catheter hub.   (79个词/句)

        该例中，“and”之前是第一个含义，“whereas”之前是第二个含义，而“suggesting”之前是第三个含义。这三个含义应该在三个独立的句子中分别表述。

C 修改后的例 4-12      

Skin swabs were cultured at the time of the removal of the catheter from seven patients with catheter-related bloodstream infection. In five of these cases (71%), the culture yielded bacteria of the same species with a DNA fingerprint pattern similar to that of the isolates from the catheter and the blood. However, a different organism grew from skin cultures in the other two patients (29%). These observations suggest that catheter infection may have originated from contamination of the catheter hub.   (平均20个词/句)

相比原句每句79个词，修改后每句平均只有20个词，理解起来容易很多。原因不仅在于句子短了，更在于不同的含义分别由不同的句子来表达。

        统计表明，科技论文的平均句长超过30个词，而报纸上多数文章的句长为15-20个词（这也是报纸通俗易懂的原因之一）。然而，并非要求句句简短，若果真如此，非但达不到引人入胜的目的，反而使文章缺乏连贯性。用于传达复杂含义的句子就需要长。作者应该明确这样一个目标，有些句子可长，有些句子可短，只要平均句长为20-22个词即可。

练习：分解以下各句

1. These results show that ATP and GTP are capable of binding to the same site in the mRNP but higher specificity is shown for ATP than for GTP, while the other nucleotides tested (CTP, UTP, AMP)did not stimulate the initiation of the translation, on the contrary , they produced some inhibition being most pronounced for UTP and CTP, suggesting that these nucleotides compete with ATP and GTP for the same site in the mRNP.  (71个词/句)

分解：These results show that ATP and GTP are capable of binding to the same site in the mRNP. Higher specificity is shown for ATP than for GTP. The other nucleotides tested (CTP, UTP, AMP) did not stimulate the initiation of the translation. On the contrary, they produced some inhibition being most pronounced for UTP and CTP, suggesting that these nucleotides compete with ATP and GTP for the same site in the mRNP.  (平均每句18个单词)

2. The Dengue virus, a Flavivirus belonging to the family Flaviviridae, which includes over 60 known human pathogens such as those causing yellow fever, Japanese encephalitis, tick-borne encephalitis, Saint Louis encephalitis, and West Nile encephalitis, is classified into four different serotypes, Types 1, 2, 3, and 4, and infection with any of these four serotypes can result in dengue fever (DF) or dengue hemorrhagic fever (DHF), which is particularly a concern during heterologous secondary dengue virus infections.   (74个词/句)

分解：The Dengue virus is a Flavivirus and belongs/belonging to the family Flaviviridae. This family includes over 60 known human pathogens such as those causing yellow fever, Japanese encephalitis, tick-borne encephalitis, Saint Louis encephalitis, and West Nile encephalitis. The Dengue virus is classified into four different serotypes, Types 1, 2, 3, and 4. Infection with any of these four serotypes can result in dengue fever (DF) or dengue hemorrhagic fever (DHF). The latter is particularly a concern during heterologous secondary dengue virus infections.  (平均每句16.4个单词)

3. Two combinations of half-wave plates and polarizing beam splitters, together with on/off photodetectors in the reflected channel, form the photon-subtraction modules that are placed in the path of the thermal light field, respectively, before and after the parametric crystal that, with the on/off photodetector in the trigger channel, forms the photon-addition module.  (52个词/句)

分解：Together with on/off photodetectors in the reflected channel, two combinations of half-Wave plates and polarizing beam splitters form the photon-subtraction modules. These modules are placed in the path of the thermal light field before and after the parametric crystal, respectively. Together with the on/off photodetector in the trigger channel, the crystal forms the photon-addition module.  (平均每句18个单词)

4. An international team of researchers says that some key elements of modern behavior were in place by 164,000 years ago, pushing back the appearance of complex tools and manipulating symbols by 25,000 to 40,000 years as evidenced by complex stone bladelets and ground red pigment—advances usually seen as hallmarks of modern behavior—coupled with the shells of mussels, abalone, and other invertebrates in a cave in South Africa, which showed that also include marine resources in their diet.  (89个词/句)

分解：An international team of researchers says that some key elements of modern behavior were in place by 164,000 years ago. This date pushes back the appearance of complex tools and manipulating symbols by 25,000 to 40,000 years. The date is evidenced by complex stone bladelets and ground red pigment advances usually seen as hallmarks of modern behavior coupled with the shells of mussels, abalone, and other invertebrates in a cave in South Africa. These ancient clambakes are the earliest evidence of humans that also include marine resources in their diet.  (平均每句22个单词)

5. Negative global coupling changes pattern formation only qualitatively if the system oscillates and can result in the formation of standing waves with wave Number 1 just like for N-NDR-systems, but for parameter values for which the migration coupling leads to the formation of Turinglike structures, the interaction of both instabilities can yield a complex wave pattern characterized by two wave numbers, n=1 and n>1.    (64个词/句)

分解：Negative global coupling changes pattern formation only qualitatively if the system oscillates. Such coupling can result in the formation of standing waves with wave Number 1 just like for N-NDR-systems. However, for parameter values for which the migration coupling leads to the formation of Turing-like structures, the interaction of both instabilities can yield a complex wave pattern characterized by two wave numbers, n = 1 and n > 1.  (21个词/句)

摘编自《科技写作与交流》(任胜利 等 译. 科学出版社, 2012年出版)