1.Practically all substance expand when heated and contract when cooled. 实际上一切物质都是热胀冷缩的。 (省译“when, and, when”) anic compounds are usually volatile and possess low melting points. 有机化合物通常容易挥发且熔点较低。 (省译动词“possess”) 3.Being stable in air at ordinary temperature ,mercury combines with oxygen if heated.水银常温下在空气中是稳 定的，但如果加热时，它会与氧化合。 1.Tertiary alcohols are very resistant to oxidation. 叔醇难于氧化 2.For the series of normal alkanes, those having one to four carbon atoms are gases. 对直链烃系而言，含有一至四个碳原子的是气体。 1.If the unsaturation is due to the presence of a triple bond then the compounds are called alkynes. 如果不饱和现象是由于叁键的存在，则该类化合物称为炔烃。 2. . A body with a negative charge possesses more elections than protons. 带负电的物体所含的电子比质子多。 (不译作“一个负电，一个物体”) 1. The zinc plate becomes more and more negatively charged with electrons ,as more atoms of zinc dissolve. 随着越来越多的锌原子溶解，锌极板上充满了电子，使它变得越来越负。 2. Gases differ from solids in that the former have greater compressibility than the latter. 气体和固体的区别在于前者比后者有更大的压缩性。 (v.n.) 3. One of the outstanding properties of carbon atom is its ability to share its electrons with other carbon atoms. 碳原子的突出性质之一是它能与其它碳原子共用其电子。 (n.v.) 4. The chlorine from salt is used for bleaching paper and textiles. 用食盐制取的氯被用来漂白纸张和纺织品。 (prep.v.) 5. In their work they pay much attention to the combination of theory with practice. 他们在工作中非常注重理论联系实际。 (n.v.) 1.In an absorption system, the refrigerant is usually ammonia. 吸收系统中，通常用氨做冷却剂。 (表语宾语) anic compounds will not usually conduct an electric current when in solution. 有机化合物的溶液通常不导电。 (状语主语) 3.The two electrons involved in a covalent bond have their spins oppositely directed. 此共价键中的两个电子的自旋方向相反。 (宾语主语) 4.None of these metals have conductivity higher than copper. 这些金属的导电率都不会超过铜。 (宾语主语) 5.The different hydrocarbons in crude oil boil at different temperatures. 原油中各种烃的沸点不同。 (谓语主语) 1. Wetting agents are required to prepare proper dispersion of fine particle powders in liquids/pastes such as color makeup. 要制备将细小粉粒适当分散在液体或膏体中的产品，如着色化妆品，需要润湿剂。 2. Alkanes undergo reactions such as cracking, alkylation, oxidation, halogenation, nitration and so on. 烷烃能进行诸如裂化、烷基化、氧化、卤化、硝化等反应。 (同位语的变序) 1 Large-scale evaporation process is being developed and used for recovering potable water from seawater. Here the condensed water is the desired product. Only a fraction of the total water in the feed is recovered , and the remainder is discarded.

目前，大规模的蒸发工艺过程正在发展并用于从海水中回收有饮用水。这里 ,冷凝水就是希望得到的产 品。但被回收的的水仅是加入的总水量的一部分,而剩余部分则被扔掉。 2 If the product is suspected of being a compound already known, it is then physically compared with the known material to establish its identity. 如果推测产物是一个已知的化合物,那就可以用物理方法将它与已知物进行比较以确定它们的一致性。 3 Careful attention must be paid to the construction of the diagram in using this equation. 用这一公式时必须认真注意其图形结构。 1.The objective of evaporation is to concentrate a solution consisting of a nonvolatile solute and a volatile solvent. 蒸发的目的是浓缩由非挥发性溶质和挥发性溶剂所组成的溶液。 ( 现在分词短语作后置定语，修饰 “solution”，译作“……的”。) 2.This led to the proposals that an acid is a chemical species that can give hydrogen ions or protons in a chemical reaction. 这就导致这样一个提法：酸是一类化学物质，它在化学反应中能给出氢离子或质子。 (定语从句译成并 列分句) 3.Potential energy that is not so obvious as kinetic energy exists in many things. 势能虽然不象动能那样明显，但它存在于许多物体之中。 (定语从句译成让步状语从句) 4.A gas occupies all of any container in which it is placed. 无论把气体装在什么容器里，都会把它充满。 (定语从句译成条件状语从句) 5.The problem whether natural rubber is a polymer with linear chain molecules has been solved. 天然橡胶是否是线型链状分子的聚合物，这个问题已经解决了。 ( 同位语作后置定语，其先行词为 “problem”，翻译时要变序) 6.Metal , which possess strength, ductility, malleability, and other remarkable properties, have suppleanted other classes of engineering materials to a considerable extent. 由于金属所具有的强度、延展性、柔韧性以及其它显著特性，因而在很大程度上已替代了其它种类的工 程材料。 (定语从句译成原因状语从句) 7.Matter has certain features or properties that enable us to recognize it easily 物质具有一定的特征或特性，所以我们能够容易地识别它。 1 Total determination of structure is also possible by means of X-ray diffraction, so that the classical goal of structure studies-ascertaining the relative spatial positions of all the atoms in any molecule-can be readily and routinely attained. 全面的结构测定也可以借助 X 射线衍射来完成，因此结构研究的经典目标—确定任何分子中所有原子的 相对空间位置—就能很快地用常规的方法来完成。 2 Valuable solvent vapors carried by a gas stream may be recovered for reuse by washing the gas with an appropriate solvent for the vapors. 被气流携带的有价值的溶剂蒸汽可用下法回收再用，即用适合于该蒸汽的溶剂洗涤该气流。 3 The idea that the four valence bonds of the carbon atom are directed toward the corners of a regular tetrahedron was advanced in 1874 by Van’t Hoff and independently by Le Bel to explain the existence of right-handed and left-handed forms of some organic compounds, which shows in the face development of crystals(enantiomorphism) and in the power of solutions to rotate the plane of polarization of a transmitted beam of polarized light either to the right to the left (optical activity). 碳原子的四个价键都指向正四面体的四角这一概念，是 1874 年由范托夫和赖贝尔各自分别提出的，以 解释某些有机化合物的右旋体或左旋体的存在，它们的存在表现在晶面的发展(对映形态)和溶液把透入的