纳米技术的目的是在纳米级别上操纵物质，以创造出具有全部分子组织形式的结构，这有可能改变未来材料和装置的生产方式，并且给人类带来巨大的经济益处。
一份研究报告描述了这些预计会出现的特种新奇材料的特性。这些材料将具有多种功能，并能够感知环境变化以及做出相应的反应。研究人员预计还会出现强度是钢铁10倍的材料、重量只有纸张的1/10的材料、具有顺磁性或者超导电性的材料、透明材料和具有更高熔点的材料。把纳米技术用于存储器，可使整个国会图书馆的信息放人一个只有糖块大小的装置中。
总统科学顾问尼尔•莱恩说，纳米技术是最可能在未来取得突破的科学和工程领域。这项技术并不只是向小型化迈进了一步，而是迈入了一个崭新的世界，在这个世界中物质的运动受量子原理的主宰。传统的解释材料性质的理论，只适用于大于临界长度100纳米的物质。如果一个结构的某个维度小于临界长度，那么物质的性质就常常无法用传统理论解释。科学家正试图在中等级别领域，即单个分子或原子级别到数十分子级别之内，发现新奇的现象。
现在知道的是，在纳米科学研究的领域内，物质的基本性质是确定的和能够操纵的。以前在硬盘涂层和制药领域内获得的突破表明，这些突破能够使价值数以十亿计美元的商业领域发生革命。最近对诸如碳纳米管、分子马达、量子点和分子开关等一些有序结构和物质所做的研究，预示着纳米技术有着广阔的发展前景。但是这份报告说，这些成果只是表明了未来的潜在发展方向。
Passage Three 3
Edmund Halley was an English scientist who lived over 200 years ago. He studied the observations of comets (彗星) ,which other scientists had made. The orbit (轨道) of one particular comet was a very difficult mathematical problem. He could not figure it out. Neither could other scientists who dealt with such problems.
However, Halley had a friend named Newton, who was a brilliant mathematician. Newton thought he had already worked out that problem, but he could not find the papers on which he had done it. He told Halley that the orbit of a comet had the shape of an ellipse (椭圆形) .
Now Halley set to work. He figured out the orbits of some of the comets that had been observed by scientists. He made a surprising discovery. The comets that appeared in the years 1531,1607, and 1682 all had the same orbit. Yet their appearances had been 75 to 76 years apart.
This seemed very strange to Halley. Three different comets followed the same
A. by doing experiments
B. by means of his own careful observation
C. by using the work of other scientists
D. by chance
我来回答:
