It often takes astronauts days to go to the moon. But will people live there? Will people ______ a city on the moon?

Some people think it is ______ . But it won’t be easy. There isn’t any oxygen (氧气) on the moon. Spaceships will need to bring oxygen from the earth. ______ will be a problem, too. How will people ______ vegetables? There isn’t any water,   ______ scientists think that they might find some ice. The energy (能量) for the city won’t be a problem—it will   ______ the sun.

Who will go to the moon? Maybe ______ will go there. The moon is an interesting place for them. It is never cloudy or rainy on the moon, so it is a good place to study (研究) the ______ and planets. Maybe we will build a university for them. We will ______ build a hotel for visitors, too. There are no beaches on the moon, but people can walk on the moon and take photos of the earth.

Will it ______? Maybe. But one thing is true: A visit to the moon hotel will be very expensive!

If you are dreaming of becoming an astronaut after you grow up, get started now! An astronaut needs a strong body and mind. Shenzhou XIII astronauts are able to live upside-down （倒立）. They do this not just during sleep, but also when eating and going to the toilet. Before they ________ space, they had lots of practice. Each upside-down training time lasted for 20 days.

Chinese astronauts aren’t just spaceship ________ but also machine repairers（修理工）and scientists. They have to know every part of the spaceship and how it ________. If something goes wrong, they’ve got to know ________ repair it. Also they do scientific experiments in space.

Shenzhou XIII astronauts know how to live in ________. They took a knife, a gun（枪）and some dye（染色水）________ them into space. If they land in forests, the knife and gun can protect them from wild animals. If they ________ the sea, the dye can colour the seawater around them yellow. This can drive ________ sea animals away.

Shenzhou XIII astronauts can’t get dizzy（眩晕）. A spaceship is not a plane. When it ________ the extra gravity force（额外重力）can break people’s bones（骨头）.

Astronauts must have strong bodies for this. They can’t get a headache or be sick. Because they have to ________ many things. They’ve got no time for sickness. Do you still have a long, long way to go?

Maybe you know a lot about the city you live in. You may even know some interesting facts about earth, but ________ do you know about Mars? Will there be ________ there just like people on Mars?

Mars is the fourth planet from the sun and it’s the most like earth, but it’s much ________ than earth because it’s farther from the sun. It’s also the only planet whose surface can be ________ from earth.

Mars is often called “the red planet” because the rocks on it have a dark ________ color. There are strong winds on Mars that can ________ dust into the hills. For many years, people have ________ Mars. They have sent instruments and robots there. Some of the robots got there, ________ most failed. NASA(美国国家宇航局) sent two robots to Mars two years ago. They wanted to ________ signs of water and life on Mars. Some day, humans will travel to Mars and have an even ________ look at our red neighbor. Maybe it could be you!