tips：对语言进行恰如其分的润饰，讲究词法、句法及篇章的粘连，增加可读性.
1 Accuracy 精确性
科技文章用词要求准确，尽量避免含糊不清和一词多义
dead air静空气
2 Parallelism整齐性
科技英语的客观性、准确性和严密性要求采用合理的句子结构。
a主从结构：有两个以上的概念
b并列结构：有两个意义对等，相同语法功能的并列成分
eg.1 制造方法可分为单件生产和批量生产，单件生产指小批量的生产，批量生产指大量相同零件的生产。
Manufacturing processes may be classified as unit production with small quantities
being made and mass production with large numbers of identical parts being
produced.
eg.2 Associated with limit loads is the proof factor, selected to ensure that if a limit load
is applied to a structure the result will not be detrimental to the functioning of the
aircraft, and the ultimate factor, which is indented to provide for the possibility of
variations in structural strength.
与极限负荷有关的是保险系数和终极系数，保险系数是选定用来保证即使极限负
荷加在飞机上，飞机也不会受到损害；终极系数则是用来预防结构强度可能发生
的变化。
3 Conciseness 简约
名词化结构在科技英语中的广泛使用使句子变成名词短语，其作用有：一、可以
较少使用人称主语，从而体现科技概念的客观性；二、可以避免结构臃肿。
eg.1由于光学纤维频带较宽，损耗较低，光源更为可靠。因此在这一领域会更具竞争力。
Larger fiber bandwidth, lower loss and more reliable optical sources would make
optical fibers more competitive in this section. 非人称名词主语
eg.2如果我们测得地震波的走时和振幅，我们就能确定地下的几何形状并估算
出与岩石速度和密度有关的声阻抗。
Seismic measurements of travel time and amplitude define the subsurface geometry
and give estimates of the acoustic impedances related to rock velocities and densities.
