A
There have been many great inventions that changed the way we live. The first great invention was one that is still very important today—the wheel. This made it easier to carry heavy things and to travel long distances. For hundreds of years after that there were few inventions that had as much effect as the wheel. Then in the early 1800s the world started to change. There was little unknown land left in the world. People did not have to explore much any more. They began to work instead to make life better. In the second half of the 19th century many great inventions were made. Among them were the camera, the electric light and the radio. These all became a big part of our life today.
The first part of the 20th century saw more great inventions. The helicopter in 1909. Movies with sound in 1926. The computer in 1928. And jet planes in 1930. This was also a time when a new material was first made. Nylon came out in 1935. It changed the kind of clothes people wear. The middle part of the 20th century brought new ways to help people get over disease.They worked very well. They made people healthier and let them live longer lives. By the 1960s most people could expect to live to be at least 60. By this time most people had a very good life.
Of course new inventions continued to be made. But man now had a desire to explore again. The world was known to man but the stars were not. Man began looking for ways to go into space. Russia made the first step. Then the United States took a step. Since then other countries, including China and Japan, have made their steps into space. In 1969 man took his biggest step away from the earth. Americans first walked on the moon. This is certainly just a beginning though. New inventions will someday allow us to do things we have never yet dreamed of.
【解题导语】 本文主要介绍了发明创造对我们生活的影响。
21．Camera was invented after ________.
A．1850 B．1950
C．1800 D．1900
解析：选A 细节理解题。本题主要考查对“In the second half of the 19th century”这个时间短语的理解， 意为“十九世纪的后50年”， 故答案为A项。
22．Why did the world start to change in the early 1800s?
A．Because there were few inventions that had as much effect as the wheel for hundreds of years.
B．Because there was little unknown land left in the world.
C．Because people did not have to explore much any more.
D．Because people began to work to make life better instead of exploring unknown world.
解析：选D 细节理解题。根据第一段中的“There was little unknown land...to make life better. ”可知， 未知的陆地已经被发现完了， 人们不再需要发现新大陆， 而是转向发明创造一些让生活过得更加美好的东西。故选D。
23．In Paragraph 2, the word “They” in the sentence “They worked very well” refers to ________.
A．helicopters, computers, jet planes, nylon
B．new ways to help people get over disease
C．new materials
D．people
解析：选B 词义猜测题。从本段第九句可知， “They”应该指的是前面说到的治疗疾病的方法。故选B。
24．The possible title for the passage might be ________.
A．Great Inventions of the 20th Century
B．How Wheels, Cameras and Computers Were Invented
C．People's Attitudes Towards Inventions
D．Great Inventions Influence Our Way of Living
解析：选D 主旨大意题。本文主要介绍发明创造怎样影响着我们的生活。故选D。
