As space science develops, man has learned more and more about space. Space is not only     1     but also dangerous. While working in space, spacemen are facing danger as well as success.

Scientists have     2     out that the radiation (辐射) is the greatest danger to spacemen. When     3     are working in space, they are in danger of the radiation from the sun and other stars, which is bad for their health.

Space     4     is also thought to be a great danger to spacemen. It’s reported that there were 9,000 man-made things flying in space. About 30% of these are satellites, 10% are     5     , and the rest are space rubbish. A small     6     of rubbish even knocks a spaceship window and     7     some damage (损坏).

Scientist are watching and reporting any possible danger all the time. They are working to deal     8     space rubbish.     9     space is really dangerous, it interests many people on the earth. In the near future, it may become     10     for people to spend a few days in a space hotel. We may even choose to leave the earth and live in space in a few years. So we should do something to help improve the space environment.

What do you know about Mars? What does it look like?

Mars is the     1     planet from the sun in our solar system and     2     after Mars, the Roman god of war. Its diameter is 53% as     3     as that of the earth. Mars gets around the sun     4     a distance of about 228 million kilometers. You can tell which planet is Mars because it is bright red in the night sky. It looks like a red     5     orange ball. It’s very beautiful. But during spring and summer, the surface of Mars is covered by strong storms. The gravity on the surface of Mars is about two-fifths as strong as it is on earth. So a person     6     weighs 90 kilos on earth weighs only 36 kilos on Mars. The     7     on Mars is between -138℃ and 28℃. The air     8     only 0.13% oxygen.

It takes a spaceship about eight months     9     Mars from the earth when the two     10     are closest to each other. Scientists are still searching for more information about Mars.

The planet Mars is the     1     and most similar planet to Earth. It is very interesting to     2    . For example, Mars has seasons with     3     weather, but other planets have the same temperatures all year round. Was there life on Mars?   

To find out, scientists need to know if Mars ever had water. In 2004, two robot explores （探测器）, or “rovers”, called Spirit and Opportunity were     4     to look for signs of water. These rovers can drive over rocks and all kinds of rough ground. They can also use cameras and send     5     back to Earth.     6     of all, the two rovers found chemicals and patterns （图文） in the rocks that were probably made by water. Then, they moved to another area and found other rocks which may have been created by water. Now scientists think there was probably water on the planet long ago. Today they are still not sure if there was life on Mars. They     7     need more information to decide. The discoveries of the two rovers answered some old questions, but they also     8     many new ones.

People began to make robots about several     1     years ago. In the past, some of the early ones looked like       2     or humans. However, they couldn’t talk and were pretty dumb. They worked like clocks and did the     3     things over and over again.

Now modern robots don’t always look like people. Some are like big machines, others are nothing but long arms attached to boxy bodies. However, modern robots are smart. Some can     4     problems on their own. Their brains are     5     and their eyes are sensors (传感器). Motors (发动机) help them     6    .

In the future, robots will learn from their mistakes more than they do now. They will be     7    . It’s possible that we will have robot judges, robot household workers, and robot factory workers. Robots will help people to do more things.

As we all know, Wang Xuan was a very famous computer scientist and     1     in the world. He is famous     2     the Chinese Language Laser Typesetting (中文激光照排系统). Laser typesetting for Chinese language was a serious problem for scientists all over the world. But Wang Xuan was not afraid to try new technology. Although he had failed many times, he never gave up. He is believed to be one of the     3     developers in printing Chinese after Bi Sheng. Wang Xuan’s amazing invention is     4     used all over the world. Wang Xuan’s story teaches us that a person should follow his own dream and try     5     best to make it come true.