Câu hỏi:

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

(1) After the Anasazi abandoned southwestern Colorado in the late 1200s or early 1300s, history’s pages are blank. The Anasazi were masons and apartment builders who occupied the deserts, river valleys, and mesas of this region for over a thousand years, building structures that have weathered the test of time.

(2) The first Europeans to visit southwestern Colorado were the ever-restless, ambitious Spanish, who sought gold, pelts, and slaves. In 1765, under orders from the Spanish governor in Santa Fe, Juan Maria Antonio Rivera led a prospecting and trading party into the region. Near the Dolores River in southwestern Colorado, he found some insignificant silver-bearing rocks, and it is thought that it was he who named the mountains nearby the Sierra de la Plata or the Silver Mountains. Rivera found little of commercial value that would interest his superiors in Santa Fe, but he did open up a route that would soon lead to the establishment of the Old Spanish Trail. This expedition and others to follow left names on the land which are only reminders we have today that the Spanish once explored this region.

(3) In 1776, one of the men who had accompanied Rivera, Andre Muniz, acted as a guide for another expedition. That party entered southwestern Colorado in search of a route west to California, traveling near today’s towns of Durango and Dolores. Along the way, they camped at the base of a large green mesa which today carries the name Mesa Verde. They were the first Europeans to record the discovery of an Anasazi archeological site in southwestern Colorado.

(4) By the early 1800s, American mountain men and trappers were exploring the area in their quest for beaver pelts. Men like Peg-leg Smith were outfitted with supplies in the crossroads trapping town of Taos, New Mexico. These adventurous American trappers were a tough bunch. They, possibly more than any other newcomers, penetrated deeply into the mountain fastness of southwestern Colorado, bringing back valuable information about the area and discovering new routes through the mountains. One of the trappers, William Becknell, the father of the Santa Fe Trail, camped in the area of Mesa Verde, where he found pottery shards, stone houses, and other Anasazi remains.

In paragraph 4, the author suggests that______.