There have been many great inventions, things 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
a long distance.
       For hundreds of years after that there were few inventions that had as much effect (作用) as the wheel.
Then in the early 1800's the word started to change. There was little unknown land left in the world. People
didn't have to explore much anymore. They began to work hard 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 (直升飞机) in 1909. Sound
movies 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 methods (方法) to help people get over diseases. They
worked very well. They made people healthier and let them live long lives. By the 1960's more 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 wish to explore again. The world is known to man but the stars are not yet. 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 earth. American 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.

A. a trip to space
B. discoveries
C. people healthier
D. life better

2. People could live longer lives because _______ worked very well in the 20th century.

A. doctors
B. medicines
C. new hospitals
D. new ways to get over diseases

3. The passage talks mainly about _______.

A. how wheel had great effect on the later inventions
B. which country made the first step into space
C. how inventions change people's lives
D. Why Nylon was very important

4. We can learn from the passage that in the future _______.

A. people's lives will be even better through great inventions
B. we can't do anything that we have never dreamed of
C. there will be fewer inventions
D. we can do everything with new inventions