46. If an engineer applies aformula or a tabulation or a curve blindly， without knowing its history，its accuracy and the limits of its sapplicability，the results that he obtains will be neither intelligent nor practical.
如果一个工程师盲目地应用一个公式、一张图表或一条曲线，而对它的来历、精确度和应用范围却一无所知，那么他所得到的结果既不明智，也不实际。 (without.……applicability介词短语作谓语applies的条件状语。that引导定语从句，在句中作obtains的宾语。)
47.The neutron carries no electrical charge and in some respects acts as though it were composed of a proton and electron combined，with the positive charge of the proton neutralized by the negative charge of the electron.
中子不带电荷，并且有点像是由质子和电子结合而成的，质子的正电荷被电子的负电荷中和了。(in somerespects，“在某些方面”，“有点”。act as though，“表现得似乎”。as though引导方式方法状语从句，其谓语常用虚拟语气。句末with引出介词复合结构，对前句的谓语作补充说明。)
48.We know that the rate of cooling from above the critical range will greatly change the structure and therefore the properties of any steel.
我们知道，从临界温度以上冷却的速率会大大改变任何一种钢的结构，从而会改变其性能。(from above.。，“从……以上”，是双重介词。)
49.Increasing problems of all kinds with fossil fuel power plants are turning power and utility companiesmoreandmore tOtheuseOfnuclearpoweredelectricgeneratingplants.
矿物燃料发电厂所产生的问题日益增多，这就促使电力公司和公用事业公司越来越倾向于采用核动力发电厂。(problem.……with，“在……方面产生的问题”，with有表示“范围”。)
50.Ever since，people have had difficulty in deciding whether the hovercraft should be ranged among ships，planes，or land vehicles—for it is something in between a boat and anaircraft.
从那以后，人们感到很难确定把这种气垫船归为哪一类：船、飞机还是车辆，因为它是一种介于船与飞机之间的交通工具。(in between，“介于两者之间”，作定语修饰something.)
51.The electric resistance of a wire is the ratio of the potential difference between it stwo ends to the current in thewire.
导线的电阻等于该导线两端之间的电位差与导线中电流的比值。(tothecurrent.……是ratio要求的。the ratio of A to B，“A与B之比”。)
52.Pollution is caused either by man's release of completely new and often artificial substances into the environment，or by releasing greatly increased amounts of a natural substance，such as oil from oil tankers into the sea.
引起污染有两种途径：一是人们经常把全新的人造物质释放到环境中，或是把大量的天然物质譬如油轮溢出的石油释放到海里。(此句为简单句，主要是由两个 by引出的短语把这个句变得复杂了。第一个into是名词~ease要求的。第二个into是动名词releasing要求的。From oil tankers作定语修饰oil.)
53.Hardening of grey cast iron may be carried out by heating the casting to above the critical range and then cooling it，usually in oil.
灰口铸铁的淬火过程是：先把铸铁加热到临界温度以上，然后加以冷却，通常在油里冷却。(heating.……to above，“把……加热到……之上”。to above是双重介词。)
54.Motion in the most general sense，conceived as the mode of existance，the inherent attribute，of matter，comprehends a11 changes and processes occurring in the universe，from mere change of place right up to thinking.
从最普遍的意义上来看，可以认为运动是物质存在的形式，是物质的固有属性，运动包括宇宙中所发生的一切变化和过程，从单纯位置的变化直到思维。(主语是motion，谓语是comprehends，被一个介词短语inthemostgeneralsense和一个分词短语conceived as……隔开了。of matter既说明existance，也说明attribute.介词短语from.……用来说明a11 changes and processes.)
55.The air is heated by the flame，expands，and thus becomes less dense. Denser air flows in from below and the result is that irregular layers of air of different densities are formed above the flame.
空气受火焰加热而膨胀，于是变得比较稀薄。较密的空气从底下流人，其结果是，火焰上 方形成了密度不同的不规则的空气层。 (flow in， “流人”。from below， “自下”， “从下面”。 above the flame作地点状语。)
56.Weather is a product of many pLysical factors operating in and on the troposphere with the principal ones being the unequal heating of the earth's surface by the sun and the rather rapid rota tion of the planet on its axis.
天气是许多自然因素在对流层中起作用并对其施加影响的结果，其中太阳对地球表面加热不均等和地球自转比较快则是主要的因素。(with引导的复合结构作定语，用来修饰factors，ones代替factors.)
57.It is the village which suffers most，for it is not easy to break the traditional bonds uniting agriculturist families to families of craftsmen，nor to dispel the idea that some one who follows the traditional calling of this caste is acting in a more“suitable” way than some one who takes up a different occupation.
乡村受害最大，因为从事农业家庭与从事手工业家庭的传统结合是很难分割的。此外，一些人认为一个人遵照等级制度的传统职业来办事要比从事不同的职业更为“合适”，这种想法也很难去掉。 (his.……which为强调句型，强调主语the village.原句是简单句，The village suffers most.for是连词，“因为”。uniting.……to，“把……与……连接”，是分词短语作定语修饰bonds.nor连词，连接两个并列成分，把to break.……和to dispel.……两个不定式短语连接起来。that.……occupation为同位语从句，用来揭示idea的概念内涵。calling意为“职业”，与occupation相呼应。 ina.……way，“以……方式”。)
58.Forging and press-production methods of shaping metal are of tremendous importance in machine-building in general，and in automobile and tractor industry in particular.
金属成形的锻压加工方法，一般在机器制造业、特别是在汽车和拖拉机工业中具有重大意义。(be of……“具有”。in general，“通常”;in particular，“特别”，这两个短语介词在句中作插入语用。)
59.In fact， in the nineteeth century people used to make gardens in the shape of aclock face，with different flowers opening at different times.
在19世纪，人们常常把花园做成钟盘形，不同的花在不同的时间开放。 (with引导的复合结构有定语的意味，用来对the shape of a clock进行修饰。)
60.The modern scientific method Was born with Galileo in the 17th century;however，the development of the natural sciences began to gain speed only in the latter part of the 18th and the early part of the 19th centuries.
现代科学方法产生于17世纪的伽利略时代;然而，只是在18世纪后期和19世纪初期，自然科学才开始迅速发展。(with Galileo.……century有表示时间与空间范围之意，这里是表示时间即伽利略时代。)
61.All of the atoms of an element contain the same number of protons in their muclei， and the atoms of one element differ from those of all other elements in the number of protons so contained.
同一种元素的所有原子的原子核中含有的质子数都是相同的，而一种元素的原子与其他一切元素的原子的不同点，就在于它们含有的质子数不同。(AdiffersfromBinC.A与B在C方面是不同的。句中in the number.……是differ要求的。)
62.The kinds of evidence for the roundness of the world that led finally to its general accep tance included such data as the shape of the shadow of the earth on the moon during an eclipse of the moon，the fact that as one sails from port on a ship the building of the port gradually seem to sink below the surface of the water，and，most convincing，the fact that it is possible to sail all around the world and return to the starting point of the voyage.
最终为人们普遍接受的有关地球是圆形的种种论据，包括：月蚀时地球投在月球表面的阴影形状;当人们乘船离开港口时，港口的建筑物似乎逐渐沉入水下;而最令人信服的是，人们环绕地球航行时，有可能又回到原来的起航点。(The kinds为主句中的主语，谓语是included.
介词as引导三个并列同位语：shape，the fact，the fact，说明data.在两个fact后的that都引出同位语从句。)
63.The technological breakthrough and the lndustrial Revolution brought with them a mastery of food production and control of infectious disease that reduced the normal death-rate to below 1.5 per cent.
技术革新和工业革命促进了食品生产，控制了传染病的流行，这使人口正常死亡率降到1.5%以下。(to below是双重介词，reduce.……tobelow，“降到……以下”。)
64.There are a few specially designed homes that are heated primarily by the sun but there is no practical and economic means for converting solar energy directly into that great convenience，electricity.
现在已有一些专门设计的住宅主要利用太阳能取暖，但还没有一种实用和经济的办法把太阳能直接转化为便于使用的电能。(介词短语for.……electridty用来修饰means.，oonverting.……into，“把……转化为……”。)
65.A balance consists of an arlTl balanced at its middle， with known weights hung on one hand and the object whose weight is to be found on the other.
天平由一个在中央平衡的臂组成，已知重量的砝码挂在平衡臂的一端，而把要称出重量的物体挂在平衡臂的另一端。 (分词短语balanced at its middle用来修饰arm.with……weights hung…是介词复合结构，用来对balance作补充说明，过去分词known作定语，修饰weights.hung是hang的过去分词。)
（责任编辑:doublejp）
