阅读下文，从各小题所给的四个选项中选出能回答所提问题或完成所给句子的最佳答案。
     There have been many great inventions or things that changed the way we live. The first great invention
  was the one that is still very important today-the wheel. This made it easier to carry heavy things and to
 travel long distance.
     For hundreds of years after that there were few inventions that 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 didn't
 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 there were the
 camera, the light and the radio. These all play a big part in our daily 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 i928,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 wore.
     The middle part of the 20th century brought new ways to help people get over diseases. They worked
  very well.  They made people healthier and allowed them to live longer. By the 1960s most people could
  expect to live to be at least 60.
     By this time most people in developed countries had a very good Life. Of course new inventions
  continued to be made. But man now had a desire (渴望) to explore again. The earth was known to man
  but the stars were not. Man began looking for ways to go into space. Russia made the first step. Then
  United States took a step. Since then other countries, including China and Japan, have made their own
 steps into space.
      In 1969 man took his biggest step away from earth. Americans first walked on the moon. This is
 certainly just a beginning, though. New inventions will some day allow us to do things we have never yet
  dreamed of.
1. This passage talks mainly about ______.
    A. why cars were very important
    B. when light was invented
    C. how inventions affect people's daily life
    D. which country made the first step into space
2. According to the passage man didn't have a desire to explore a lot ______.
    A.  at the beginning of 1800s  
    B.  in the 1960s
    C. since the 1900s            
    D. from the 1800s to 1960s
3.  In the 1800s, people began to work in order to make ______.
    A. explorations             
    B. their life better
    C. discoveries              
    D. a trip to space
4.  Nylon came out five years later than ______.
    A. radio                  
    B. camera
    C. jet planes                
    D. movies
5.  People can live longer lives because ______ that help cure diseases have worked very well.
    A. doctors                  
    B. new ways
    C. medicines                
    D. new hospitals