完形填空。 The computer is a very wonderful machine, and it is so 1 today that it seems we 2 live or work without it. Computers are used in many 3 in offices, in factories, in big shops, at schools, and even at home. With the computer people are living a better 4 . The computer is one of the greatest inventions in the 5 century. The first computer was built in America which was named Eninc, and it was not only very 6 , but also quite heavy.  It was as big as two rooms! But the computer is developing very fast.  Today they are becoming smaller and smaller, lighter and lighter, and 7 faster and faster. There are so many kinds of different computers in the market that you can easily choose one that you like best. As the computer can do a lot of things for people, it helps us to learn about the real world. With the computer you can 8 an E-mail just in a few seconds to your friend to receive your 9 . Now you can see the computer really gives us a very nice picture about the world of tomorrow. So as students in the 21st century, we have to work hard and learn how to 10 the computer very well. Don't you think so? (     )1. A. beautiful (     )2. A. can (     )3. A. roads (     )4. A. life (     )5. A. 18th (     )6. A. useful (     )7. A. studying (     )8. A. give (     )9. A. letter (     )10.A. get B. interesting B. cannot B. streets B. friend B. 19th B. large B. teaching B. take B. book B. use C. popular C. must C. crossings C. family C. 20th C. small C. walking C. post C. help C. read D. enjoyable D.mustn't D. ways D. country D. 21st D. cheap D. working D. send D. message D. write