1. When the cancer cells have invaded surrounding tissue or have spread through the blood or lymph to other parts of the body, complete removal becomes impossible.在癌症细胞感染了周围组织或通过血管或淋巴扩散到全身后就不能完全割除了。
2. Factories everywhere are demanding for the new instruments with which it is possible to perform many experiments.各地的工厂都需要这种新仪器，用它能作许多试验。
3. She obtain the honor by all students for her excellent teaching.她出色的教学水平赢得了广大学生的尊敬。
4. Gas are frequently considered to incompressible.通常认为气体是可压缩的，而液体是不可压缩的。
5. The ancients tried unsuccessfully to explain how a rainbow is formed. 古代人曾经试图说明虹是怎样产生的，但没有成功。
junior
expensive的同义词6. There (in Germany)a group of amateur enthusiasts, inspired by dreams of inter- planetary travel, were conducting their own, occasionally fatal, experiments on liquid-fuelled
短裙英文
piggybankrockets.德国有一些业余的火箭爱好者，在进行星旅行时的梦想激励下进行液体燃烧火箭实验，它们的实验有时是非常危险的。
7. With the deve1opment of modern electrical engineering, power can be transmitted to wherever it is needed.随着现代电气工程的发展，人们能把电力输送到所需的的任何地方。
8. Six medical scientists were honored in 1973 by the Gairdner Foundation of Toronto, Canada, for outstanding rearch.由于杰出的研究工作，六位科学家荣获了加拿大多伦多盖尔德纳基金的颁发的奖励。
9. The first practical steam engine was invented by James Watt in 1776 . This is generally accepted as the beginning of the Industrial Revolution Then，the screw cutting lathe，invented by Henry Maudslay in 1797，became one of the first and most important of the power driven machine tools.第一个能够实际应用的蒸气机是由詹姆斯.瓦特在1776发明的，一般认为，那时候为工业革命的开始。亨利.莫尔兹在1797年发明的螺纹加工机床成为第一批重要的动力驱动的机床之一。
10. In order to detect the time when a cutting tool should be changed，most modern machines are equipped with indicators that show the horpower ud during the machining operation When a tool becomes dull more horpower is required for the operation．which will show on the indicator．When this occurs．the tool should he reconditioned immediately.为了知道什么时侯该换刀具，大部分现代机床都安装了指示器来显示切削加工所耗的功率。当刀具用钝时，加工就需耗更多的功率，并由指示器显示出来。一旦发生这种情况就应立即打磨刀具。
tip网络用语
fireflies11. All products that come cut of industry consist of at least one and often many types of materials. The most obvious example is the automobile．A car contains a wide variety of materials, ranging from glass to steel to rubber, plus numerous other metals and plastic.工业生产的一切产品至少都是用一种，经常是许多种材料制成的。最明显的例子便是汽车，生产一辆汽车需用大量不同的材料，包括玻璃、钢材、橡胶以及许多其他的金属和塑料。aerials
正格
12． The properties of a material originate from the internal structure of that material. Thi
s is analogous to saying that the operation of a TV t depends on the components and circuits within that t．The internal structure of materials involve atoms，and the way atoms are associated with their neighbors into crystals，molecules，and microstructures.一种材料的性能来自其内部结构。这好比说，一台电视机的运行依赖于电视机内部的零件和电路。材料的内部结构涉及到由原子和原子之间的相互关联而形成的晶体、分子和微结构。
13． Characteristically，metals are opaque，ductile，and good conductor of heat and electricity Plastics(or polymers)，which usually contain light elements，and therefore have relatively low density，are generally insulators，and are flexible and formable at relatively low temperatures．Ceramics，which contain compounds of both metallic and non metallic elements，are usually relatively resistant to vere mechanical．Thermal，and chemical condition.从特点来看，金属不透明，有韧性、是热和电的良导体。塑料(聚合物)通常包含轻元素，因而密度较低，一般为绝缘体，并能在较低温度下弯折和成形。陶瓷是由金属和非金属元素的化合物构成，通常能抗恶劣的机械、温度和化学环境。
14． Plastics and ceramics are nonmetals；however，plastics may be machined like metals, Plastics are classified into two types—thermoplastics and thermots. The thermoplastics can be shaped and reshaped by heat and pressure but thermots can not be reshaped becau they undergo chemical changes as they harden. Ceramics are often employed by e11gineers when materials which call withstand high temperature are needed．塑料和陶瓷是非金属。然而，塑料可象金属一样进行加工。塑料分成两类：热塑塑料和热固塑料。热塑塑料可通过加热相加压成形和再成形，而热固塑料却由于在硬化过程中发生了化学变化而不能再成形。工程师在需用耐高温材料时常常选用陶瓷。
15． During the surface-grinding operations, heavy workpieces are either held in fixtures or clamped on the machine table by strap clamps and the like, whereas smaller workpieces are usually held by magnetic chucks.在表面磨削加工过程中，重的工件或者装在夹具上或者用压板或类似的东西压在机床工作台上，而小的工件通常用磁性卡盘装夹。
shut up什么意思中文
16． Internal grinding is employed for grinding relatively short holes. as shown in Fig. 6. 3.
The workpiece is held in a chuck or a special fixture. Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.内圆磨削用来磨削想对较短的孔，如图6.3所示，工件被夹紧在卡盘或一个特殊的夹具上，在加工过程中，砂轮和工件都旋转，在纵向方向是作进给运动。
17． Conquently, the peripheral velocity of the regulating wheel can be resolved into two components, namely, workpiece rotational speed and longitudinal feed. The can be given by the following equations.结果，导向轮的周向速度被分解成两个方向，即工件的旋转速度和纵向进给速度，它们可以用下面公式表示。
dsa是什么18． The main dimensions of a grinding wheel are the outside diameter D, the bore diameter d, and the height H. The dimensions vary widely, depending upon the grinding process for which the wheel is to be ud.砂轮的主要尺寸是外径D，孔径d和高度H，这些尺寸参数变化很大，它们取决于砂轮用于的磨削过程。
19． As you may expect, the grain size of the abrasive particles(颗粒，微粒) of the wheel plays a fundamental role in determining the quality of ground surface obtained.正如你想
的，砂轮颗粒的大小在决定获得的磨削质量起着决定的作用。
20. Grinding makes u of abrasive particles to do the cutting Grinding operations may be classified asprecision or nonprecision，depending on the purpo．Precision grinding is concerned with grinding to clo tolerances and very smooth finish，Nonprecison grinding involves the removal of al where accuracy is not important.磨削利用磨粒来进行切削。磨削可根据不同的目的分为精磨和非精磨。精磨是为了紧公差和高光面修整的磨削，而非精磨是精确度要求不高的金属切削。
