The journey to the moon has been the first step towards exploration（探险）in space. The distance between the moon and Earth is very short indeed（的确）when compared with the distances between Earth and the other planets. Venus, the nearest planet to Earth, is millions of miles away!

Travelling to the planets will be man’s next aim. Such travels will be more challenging（有挑战性）than the trip to the moon and certainly more adventurous. In 1976 two American spaceships, Vikings 1 and 2, landed on Mars trying to discover whether that planet has any life out it. So far scientists are not sure about that.

Scientists have discovered that the surface of Venus is very hot and it is almost certain that there is no life there. Also the atmosphere（大气）of Venus is extremely dense（稠）and the pressure is nearly a hundred times greater than that of the Earth’s atmosphere.

Scientists believe man may find planets just like our home, Earth, but man should realize Earth will be the only home for a long time and begin to love and care for it.

3 . Believe it or not, the day when you can go to the moon is coming soon. You can go into space _______ space shuttle (太空船). It _______ about three days for the shuttle to go from the earth to the moon. The shuttle flies a long way to a space station. You can stay there for a short rest and then it will _______ you to the moon.

Now you can jump out of the shuttle. But you mustn’t take off your spacesuit (太空服), because it is very hot in the daytime and very cold at night on the _______. The moon is much smaller than the earth. Things are _______ on the moon than they are on the earth. You can jump high every time you take a step. You will find that it is never tiring to walk on the moon. You don’t need to take an umbrella or a raincoat with you _______ there is no rain on the moon. You can hear _______ because there is no air on the moon. And there are no animals or other living things there.       

The moon moves more _______ than the earth, so one day on the moon is as long as two weeks on the earth and one night is just as long as two weeks on the earth. What could you do in _______ long days and nights and in a silent world? Now ________ are trying to make the best of the moon. But our earth is really a far better place to live, as long as we take good care of it.

4 . We have always been interested in the Moon. 2, 000 years ago, people already knew it moves around the Earth and where it would be in the sky at different times of the year.     1    

When scientists could use telescopes to study the Moon more closely, their ideas began to change. They could see the Moon was made of rocks.     2     And they believed the Moon had once been a planet. It was caught in Earth’s gravity millions of years ago.

In 1969, Moon rocks were finally brought to the Earth by astronauts.     3     To their surprise, scientists found that the Moon and the Earth are made of the same things except for water.     4    

After years of study, some scientists think that the Moon was once part of the Earth. They believe maybe 4 million years ago, something hit the Earth.     5     These rocks slowly joined together and after many years became the Moon.

In the future, even though our ideas about the Moon may change again, we will still be interested in it.

5 . Like many other countries around the world, China hopes to explore the moon. It has already done so with several probes (探测器) and lunar rover (月球车). But it has even bigger plans to put a man on the moon in the near future.

Yang Liwei, China’s first man in space, said that it will “not take long” for a manned mission (任务) to get official agreement and money support, according to the Xinhua News Agency.

China’s space program is still young compared to those of the United States and Russia. But it has already made great achievements in exploring the moon. Its moon mission began with Chang’e 1, an unmanned orbital (轨道) probe that was sent up in October, 2007. It collected data that was used to create a 3-D map of the moon’s surface.

China achieved another achievement with the Chang’e 3 mission. For this mission, China’s first lunar rover, Yutu, successfully landed on the moon.

For China’s space program, it was another great achievement that Chang’e 4, the second lunar rover successfully landed on the moon’s far side, an area that has not yet been explored, in December, 2018.

China will follow Chang’e 4 with a series of other lunar mission. These missions will include taking lunar soil and rock samples, building “moon base”, and hopefully landing a human on the moon’s surface around 2030, according to Zhao Xiaojin, a senior official at the China Academy of Space Technology.

Last year, when Yang Liwei was asked if he had any plans to visit the moon himself, he replied, “If I am given the chance, no problem!” It is likely that many other Chinese share Yang’s excitement about this new stage of China’s space exploration efforts.

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

Scientists have found out that the radiation (辐射) is the greatest danger to spacemen in space. When spacemen are working in space, they are in danger of the radiation from the sun and other stars, which is bad for their health. The harm of the radiation won’t be discovered until their children or even grandchildren are born. Some special medicine may work a little, but no really effective (有效的) medicine has been found so far.

Space junk 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 spaceships, and the rest are space junk. An explosion (爆炸) in space in 1999 made a cloud of 300,000 fragments, each at least 4mm in size, and even a small piece of these knocked against a spaceship window and did some damage (损坏).

Scientists are watching and reporting any possible danger all the time. They are working on helpful ways to do with space junk. Although space is really dangerous, it interests everyone on the earth. In the near future, it may become possible 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 care for space and do something to help improve the space environment.

9 . Many people know that rubbish is a big problem on the planet Earth. What many people don’t know is that junk（垃圾）has become a problem in outer space too.

According to BBC News, there are more than 22, 000 pieces of space junk floating around the earth. And these are just the things that we can see from the surface of the earth by telescopes （望远镜）. There are also millions of smaller pieces of junk that we can’t see.

Objects, like bits of old space rockets（火箭）or satellites（卫星）, move around the planet at very high speed so fast that even a very small piece can break important satellites or become dangerous to astronauts. If the tiniest piece of junk crashed into a spaceship, it could damage （损害）the space tool.

To make things worse, when two objects in space crash, they break into many smaller pieces. For example, when a U.S. satellite hit an old Russian rocket in 2009, it broke into more than 2,000 pieces, increasing the amount of space junk.

To reduce additional （额外的）space junk, countries have agreed that all new space tools can only stay in space for 25 years at most. Each tool must be built to fall safely into the earth’s atmosphere （大气层）after that time. In the upper parts of the atmosphere, it will burn up.

Many scientists also suggest different ways to clean up space junk. In England, scientists are testing a special net that can be sent into space junk. The net catches the junk and then pulls it into the earth's atmosphere to burn up. The Germans are building robots that can collect pieces of space junk and bring them back to Earth to be safely dealt with.

“The problem is becoming more challenging because we’re sending more objects into space to help people use their mobile phones and computers,” says Marco Castronuovo, an Italian space researcher.