A.At present，almost all our energy comes from fossil fuels．
现在，几乎我们所有的能源都来自矿物燃料。
A.All substances are made of very small parts called molecules．
中原汽车网所有物质都是由叫做分子的微粒组成的。
A.After WorldWar Ⅱ，the energy derived from burning the various fractions of petroleum exceeded that of coal．二战后，燃烧各种石油馏分所产生的能量超过了燃烧煤所产生的能量。
A.Almost everything in the world has been improved or changed in the last hundred years as a result of technology． 由于技术进步的原因，在过去的一百年里，几乎世界上的每一种事物都有所改善和变化。(现在完成时)
A.At the present moment，petroleum is being used up much more quickly．
目前，石油正在以更快的速度被消耗掉。(现在进行时)
A.A number of different coolants had been employed，including water，carbon dioxide and liquid metals． 用过的冷却剂多种多样，包括水、二氧化碳和液态金属。
A.About three hundred years ago a mathematician made a system using only 1 and 0，but he didn't realize how much this binary system would some day be used．
(过去将来时)大约三百年前，一位数学家制订了一个只用l和0的计数系统，但是，他不知道这种二进制系统将会有多大用处。
A.At the present moment，petroleum is being used up much more quickly．
目前，石油正以更快的速度被消耗。
A.As engineering becomes more and more precise，better accuracies than this will be needed．随着工程需求越来越精确，我们需要比这更高的精确度。(一般将来时)
A.Almost all other substances are similarly affected by temperature．
几乎其它所有物体都同样受温度的影响。
A.A11 he had to do then was to stop the car and shut the doors．
接着他要做的是停下车并关好车门。
A.Ask your teacher how to pronounce the word．问问你的老师这个单词怎样发音。
A.A computer needs to have a program in order to work．
为了工作，计算机需要设汁程序。
AA.All these materials come from living things．所有这些材料都来自生物。                   
AA.A basic knowledge of science can help you to understand both the questions and the answers． 基础科学知识能帮助人们理解这些问题及其答案。
AA.A lorry traveling at 70 mph has more momentum than a car traveling at 70 mph．以时速70英里行驶的卡车比时速为70英里的小汽车的动量大。
AA.All nationalities，in all foreign countries，can be found judging what they see，hear，t
aste and smell according to their own habits and customs． 所有民族到了外国，往往总是按照自己的风俗习惯去判断他们所看到、听到、品味和嗅到的东西。
AA.And those who are going to keep up the wonderful progress being made in science and engineering need math more than anyone else does．
那些想继续保持在科学和工程上取得惊人进步的人比其他人更需要数学。
AA.All substances are made of very small parts called molecules.
所有的物质都是由称为分子的微粒组成的。
AA.A person can be weightless，if desired． 如果愿意的话，人可以失重。
AA.Any combination of ones or zeros representing a character can be written magnetically or read back when needed．表示一个字符的1或0的组合都能在需要时被磁写或读取。
AA.A nylon shirt lasts longer than a cotton shirt．尼龙衬衫要比棉衬衫耐穿。
AA.All of the different kinds of science are important and interesting．
所有多种多样的科学都很重要而且有趣。
AA.A11 but 20 of the over 100 elements identified to date are metals。
在迄今为止已确认的100多种元素中，除20种外，其它元素都是金属。
AA.Autumn is the best season of the year． 秋天是一年中最好的季节。
AA.Are you or he going to do it? 是你还是他去做这件事?
AA.A number of other things such as wood，plants and oil are made very largely of carbon． 其他许多东西如木头、植物和油的大部分都由碳组成。
AA.All work and no play makes Jack a dull boy． 只工作不玩耍，聪明的孩子也变傻。
AA.At no time should we lose our vigilance．我们在任何时候也不要丧失警惕性。
AA.And yet this is the result：here a complete mastery of the language，however stupid the child．然而结果却是：不管学话的幼童多笨，却能完全地掌握语言。
AA.After roads come cities． 先有道路，后有城市。
AA.An acquaintance of mine who lives in England and had never been outside it until last summer decided to go over to France for a trip．
我有一位熟人常住英国，从未出过国，去年夏天决定到法国去旅游。
AA.As the apple falls，it loses potential energy because its height decreases．
当苹果下落时，因其高度下降，便失去其势能。
AA.As the temperature of the environment rises，the rate of heat loss from the body becomes less and less．随着环境温度的升高，热量损失也越来越少。
AA.And where there is shale there is likely to be oil．
在有页岩的地方，就有可能有石油。
AA.A physicist designs his measuring teaching technique so that disturbance of quantity measured is smaller that his experimental error．
物理学家设计测量方法以便使所测物理量的干扰少于实验误差。
AA.A body will float if its density is less than that of the liquid in which it is immersed．假如物体的密度小于它所沉浸的液体的密度，它将浮在其上。
AA.A doctor performing an operation in a hospital can now use a laser to make a far more precise cut than any knife is capable of．
现在医院的医生可以使用激光做手术，而且比任何手术刀所做的手术要准确得多。
AA.Although it is less abundant in the earth，more chemically active and harder to extract than aluminum，it is present in sea water and that means there is almost an endless supply of it.尽管与铝相比，它在地壳内的储量少，化学性质更活跃，且更加难以提炼，但它存在于海水中，这就意味着它几乎是无穷无尽的。
A．After people has learned that magnets attract things，centuries passed before they took note of the fact that magnets sometimes also repel things．人们早已知道了磁体能吸引别的物体，又过了几百年，才注意到磁体也有时排斥物体这一事实。