Nanotechnology is the creation and use of materials or devices at extremely small scales. These materials or devices fall in the range of 1 to 100 nanometers (nm). One nm is equal to one-billionth of a meter (.000000001 m), which is about 50,000 times smaller than the diameter of a human hair. Scientists refer to the dimensional range of 1 to 100 nm as the nanoscale, and materials at this scale are called nanocrystals or nanomaterials.

     The nanoscale is unique because nothing solid can be made any smaller. It is also unique because many of the mechanisms of the biological and physical world operate on length scales from 0.1 to 100 nm. At these dimensions materials exhibit different physical properties; thus scientists expect that many novel effects at the nanoscale will be discovered and used for breakthrough technologies.

     A number of important breakthroughs have already occurred in nanotechnology. These developments are found in products used throughout the world. Some examples are catalytic converters in automobiles that help remove air pollutants, devices in computers that read from and write to the hard disk, certain sunscreens and cosmetics that transparently block harmful radiation from the Sun, and special coatings for sports clothes and gear that help improve the gear and possibly enhance the athlete’s performance. Still, many scientists, engineers, and technologists believe they have only scratched the surface of nanotechnology’s potential.

     Nanotechnology is in its infancy, and no one can predict with accuracy what will result from the full flowering of the field over the next several decades. Many scientists believe it can be said with confidence, however, that nanotechnology will have a major impact on medicine and health care; energy production and conservation; environmental cleanup and protection; electronics, computers, and sensors; and world security and defense.

(Adapted from: Encarta DVD 2009)

Question 31: What is the passage mainly about?

     A. A new physical property of matters in nature

     B. A way of manufacturing technological products

     C. An introduction to a new technology

     D. An overview of how technology will develop

Question 32: The word “that” in paragraph 3 refers to ________ .

     A. converters                     B. automobiles                   C. technologies                  D. properties

Question 33: The word “novel” is closest in meaning to ________ .

     A. causing a chemical reaction to happen faster         B. being different from anything known before  

     C. being important enough to be noticed                    D. being the only one of its kind

Question 34: Which of the following statements is NOT true about nanotechnology according to the passage?

     A. No other products are smaller than those made by nanotechnology.

     B. Nanotechnology allows the production of things at extremely small scales.

     C. Nanotechnology has seen a number of important breakthroughs.

     D. Medicine and healthcare will be greatly affected by nanotechnology.

Question 35: According to scientists, materials at the nanoscale are called ________.

     A. nanocrystals or nanomaterials                                 B. nanotechnology’s potential

     C. nanotechnology’s potential                                     D. catalytic converters

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