Many kids are crazy about space. Last month, a space agency (机构) told the public that they were _________ “a planet protection officer.” Some people laughed at the funny job title, but a 9-year-old boy took the information _________. He wrote a letter to the agency, saying that he wanted the job.

“Dear sirs, my name is Sam Lee. I think I am the _________ person for the job,” he wrote.

What are Sam’s _________? For one, he wrote, “My sister says I act like an alien (外星人)” Sam also said he had watched almost all the _________ movies he could find. His last sentence may touch people’s hearts: “I am young, so I can learn to think like an alien.”

Sam soon got a _________ from Bill Black, director of the agency. “We have received your letter. It is great that you are interested in the job. This job is to _________ the earth from germs (细菌) on things brought back from other planets.” Bill ended the letter with some warm words, _________ Sam to study hard and do well in school. “We hope to _________ you at the agency one day.” he wrote.

“Among kids, there are __________ space scientists.” Bill told a newspaper. “We think of this letter as a chance that may forever change our kids’ life.”

You might have seen beautiful rainbows in the sky before. They form when sunlight falls on water drops in the air. But in fact, moonlight can also create rainbows in the same way. They are called “moonbows”. They are similar to rainbows, but they are created by moonlight instead of direct sunlight.

Moonbows are rarer than rainbows. Different weather and astronomical （天文学的）conditions have to be just right for moonbows to be created.

The moon has to be very low in the sky-only 42 degrees from the horizon （地平线）. The moon period has to be a full moon or nearly full. The sky must be very dark for a moonbow to be watched clearly-any bright light can obscure it. Water drops must appear in the air in the opposite direction of the moon.

Moonbows appear on the opposite side of the moon and usually look white to the human eye. This is because their colors are not bright enough to be noticed by the human eye. It is possible, however, to view the colors in a moonbow using long exposure （长时间曝光）photography.

Moonbows more often appear in some locations around the world. Most of these locations usually have waterfalls, which create thin fog in the air. Some of these locations are the Yosemite National Park in California and Cumberland Falls State Resort Park in Kentucky, US; Victoria Falls on the border of Zambia and Zimbabwe; and Waimea in Hawaii, US.

Moonbows do really happen. So at a certain time and a certain place, when a moonbow happens to appear, you can’t miss it if you’re right there.

4 . China has named the nation’s first Mars rover（火星车）ZhuRong. For all of us, Zhu Rong is a well-suited name.

In an ancient Chinese story, Zhu Rong had the face of a man and the body of an animal. H rode on two dragons. When he had a big fight with Gong Gong, the god of water, Zhu Rong won. But after the fight, the human world came into complete darkness. Then he brought fire from heaven（天国）to the world.

“Zhu Rong is regarded as the earliest god of fire in traditional Chinese culture,” a space official said. “The first Mars rover was named Zhu Rong. The name symbolizes（象征）light and hope for space exploration（探索）in our country, and means to guide humans to continue exploration.”

After leaving the earth last summer, Zhu Rong circled Mars for several months and landed on it in May. In recent years, our country has sent up the world’s first quanturn satellite（量子卫星）, and Chang’e-4 has made a soft landing on the moon. We have made great progress in space technology and will soon start building our own space station.

5 . Some people believe that humans could live on the planet Mars by the year 2100. Our own planet, the Earth, is becoming more and more c    1     and polluted because of the increase in population. It is hoped that people could start to b    2     a better world on Mars. Here is what life there could be like.

At present, our spaceship are too slow to carry large numbers of passengers to Mars-it would take months, with the development of t    3    , by the year 2100, the journey might only take about 20 minutes in spaceship that travel at the speed of light! However, the spaceship would travel so fast that the journey to Mars might be quite uncomfortable. Many people would f    4     ill.

Humans cannot survive (活下来) without water, oxygen or f    5    . So far, nobody knows whether there would be enough water or oxygen on Mars for people there. Moreover, scientists are not sure whether plants could g    6     on Mars. Food would most probably be in the form of pills (药丸) and would not be so tasty.

Gravity(重力) could be a    7     problem. The gravity on Mars is only about three-eighths of that on the Earth. People would have to wear boots that are specially designed(设计) to stop themselves from floating(飘) off into space.

C    8     with life on the Earth, life on Mars would be better in some ways. People would have more space. They might live in houses with huge comfortable rooms. What’s m    9    , robots would do most of their work so that they could have more time to relax. There would probably be no schools on Mars. Every student would have a computer at home connected to an interplanetary network, they would study at online schools with “e-teachers”.

Life on Mars would be i    10     as well as challenging(有挑战性的).

Ten, nine, eight, seven...With a shining flame (火焰) behind, the fifth Long March 5 Carrier Rocket with Chang’e 5 lunar probe took off at 4:30 am on Nov 24.    1    And it succeeded returning to China on December 17th.

Because of this moon exploration (探月任务), Chang’e 5 is named after the Chinese moon Goddess Chang’e. Its weight is 8.2 tons which is an unbelievable amount to fly into the space.    2    

Chang’e 5 has carried out the hardest task in its historical exploration program.    3    This task lasted about 23 days. It has made China the third county after the US and former Soviet Union ( 苏联) which brought back samples (样品) from the moon. In 1976, the former Soviet Union brought 170.1 grams of lunar sample. This time, Chang’e 5 brought back a larger sample than former crafts and explored a new area of the moon.    4    

Besides the great increase in sample, Chang’e 5 landed on the northwest part of Oceanus Procellarum (风暴洋), where no probes have visited before. The samples got there might be 1.2 billion years old.    5    It is said that Chinese scientists and those from other countries all have a chance to get the lunar samples for research and it is believed that humans will get into a new time to study the history, the resources of the moon.

8 . Each astronaut has a special job to do as part of the team. Some astronauts learn how to put things together so they become good at fixing things. This is important because if something on a spaceship breaks the astronauts must be able to fix it themselves. Some astronauts are pilots who know how to fly airplanes. These astronauts have to study how to fly a spaceship. Other astronauts learn mostly about science. Their job is to learn how living things change when they are in space.

Although each astronaut has a special job, each of them has to learn how to work where there is no gravity(地球引力). When they are in a spaceship that is moving around the Earth, they can feel as if they didn't weigh anything. They are able to float(漂浮).

This sounds like fun, but it's not that fun. People are used to being on the Earth, but some people stay out in space for months. A lot of strange things happen to the body when it floats for that long.

Astronauts sometimes feel sick in space. It takes them a few days to get used to not weighing anything and being able to float.

Being in space also makes the astronauts’ legs weak. They call this “bird legs”. To help keep their legs strong, astronauts have to do exercise when they are in space.