Imagine aguitar so tiny that you can ’t seeit with the human eye, but you can hearsound whe n its strings are pulled. Some people say the future is big, but when it comes to technology, the world is getting smaller. Nanotechnology( 纳米技术 )is the science that deals with doing things in a very small way, and it is being studied and developed all over the world. Micro-machines too small to been seen by the eye are being designed to do many things. And these machines no larger than in diameter than a human hair, are extremely powerful. Many scientists say nanotechnology will produce the next industrial revolution( 工业革命 ). Nano comes from the Greek word dwarf . A nanometer is one-billion of a meter, The period of the end of this sentence can contain about 100 micrometers, which in equal to 100,000 nanometers.To understandthis new technology, we have to get rid of the normal ideas of size and strength. Minute( 微 小 的 ) robots , called “ nanorobots ” are being developed in the revolutionize manufacturing. Instead of cars being produced on assembling line, for example, scientist predict that carscan be built in a giant container into which raw material and machines have beenplaced. Thousands of nanorobots will direct the processandtell the machine what to do. Micro-machines can also be used to make our environment safer. Today, poison chemicals are stored in containers or transported by trucks or trains. This is sometimes result in dangerous spills. But with nanotechnology, manufacturers could have their own tiny chemical factories. The produce would be no bigger than a sugar cube and would manufacture exactly the amount of chemicals neededat the moment. No chemicals would needto be stored. The workplace would be safer,and the environment would be cleaner. The author mentions guitar at the beginning of the passagein order to_______ . A.introduce the knowledge of guitar B.introduce the topic of nanotechnology C.show his or her own interest in music D.describe the craft of making musical instruments According to the passage,why does the nanotechnology lead to the next industrial revolution?A.Micro-machines are tiny but beautiful B.Micro-machines are strong but smart C.Micro-machines are small but powerful D.Micro-machines are cute and varied The word dwarf in Pra.3 is closestin meaning to ?A.clever B.slow C.quick D.minute With nanotechnology, where will carsprobably be produced ?A.On assembleline B.In huge containers C.Inside the micro-machines D.Inside the nanorobots Which of the following is NOT the causes leading to cleaner environment by adopting nanotechnology?A.There will be less dangerousspills. B.The amount of produced chemicals can be precisely controlled. C.Micro-factories neednot store chemicals. D.The factories will be of large size.