【单选题】

There have been many great inventions that change the way we live. The first great (16) was one that is still very important today—the wheel. This made it easy for man (17) heavy things and to travel long distances. For hundreds of years after that, there were (18) inventions that had as much effect as the wheel. Then in the early 1800’s the world started to change (19) . There was little unknown land left in the worlD、People did not have to explore much any more. In the second half of the 19th century many great inventions were made. (20) them were the camera, the electric light and the radio. These have all become a big part of our life today.

The first part of the 20th century saw more great inventions. The helicopter in 1909. Movies (21) sound in 1926. The computer in 1928.And jet planes in 1930. This was also a time when a new (22) was first made. Nylon came out in 1935. It changed the kind of clothes people wear. Of course new inventions continued to be made. Man began looking (23) ways to go into space. Russia made the first step. Then the United States took another. Since then other countries, includingChina and Japan, (24) their steps into space. In 1969 man took his biggest step away from earth. (25) first walked on the moon. This was certainly just a beginning. New inventions will someday allow us to do things we have never yet dreamed of.
A．for B．out
C．after D．around