Even though their work was very difficult and dangerous, cowboys did not earn much money. They were paid badly. Yet cowboys liked their way of life. They lived in a wild and open country. They lived a life of adventure and freedom.

　　11. A cowboy is a symbol of .

　　A. courage and adventure B. a hard life and big pay

　　C. movies in the past D. cows and other cattle

　　12. The cowboys’ job was .

　　A. to be a hero in real life B. to be a hero of the movie

　　C. to take care of cattle D. to be a dangerous rustler

　　13. During a cattle driver, cowboys took a group of cows from a wild and open country to .

　　A. the West states and Texas B. the cities of the East States

　　C. the people who eat beef in cities D. the railroad towns hundred miles away

　　14. On their way of cattle drivers, the cowboys protected the cattle by .

　　A. burning a mark on their cows B. keeping an eye on cattle thieves

　　C. making the trip more dangerous D. looking after eight cows each person

　　15. Cowboys enjoyed themselves because .

　　A. they liked their way of life B. they made a lot of money

　　C. they had a vary difficult job D. they were heroes in movies

　　Passage 4

　　Questions 16 to 20 are based on the following passage:

　　Successful innovations have driven many older technologies to extinction and have resulted in higher productivity, greater consumption of energy, increased demand of raw materials, accelerated flow of materials through the economy and increased quantities of metals and other substances in use each person. The history of industrial development abounds with examples.

　　In 1870, horses and mules were the prime source of power on U.S. farms. One horse or mule was required to support four human beings a ratio that remained almost constant for many decades. At that time, had a national commission been asked to forecast the population for 1970, its answer probably would have depended on whether its consultants were of an economic or technological turn of mind. Had they been “economists”, they would probably have projected the 1970 horses or mule population to be more than 50 million. Had they been “technologists”, they would have recognized that the power of steam had already been harnessed to industry and to learn and ocean transport. They would have recognized further that it would be the prime source of power on the farm. It would have been difficult for them to avoid the conclusion that the horse and mule population would decline rapidly.

　　16. According to the passage, what supplied most of the power on U.S. farms in 1870?

　　A. Animals B. Humans C. Engines D. Water

　　17. Which of the following is NOT mentioned by the author as a consequence of new technological developments?

　　A. Older technologies die away. B. The quality of life is Improved.

　　C. Overall productivity increase. D. More raw materials become necessary.

　　18. It can be inferred from the passage that by 1870 .

　　A. technology began to be more economical

　　B. the steam engine had been invented

　　C. the U.S. horse population was about 10 million

　　D. a national commission was about 10 million

　　19. In the second paragraph, the author suggests that “economists” would .

　　A. plan the economy through yearly forecasts

　　B. fail to consider the influence of technological innovation

　　C. value the economic contribution of farm animals

　　D. consult the national commission on the economy