Smog is a big problem in many Chinese cities. But it seems that besides wearing a mask, few of us know what has caused the smog and what to do to beat it. In fact, burning too much coal and oil are the main causes of PM2.5 and smog (雾霾).

    To solve the problem, we should clean our coal and oil or replace them with cleaner energy such as natural gas. We ordinary people can do something to help control smog, too.

    What can we do to help beat the smog?

    Choose to take public transportation. Though many people have their own cars, they had better take public transportation, such as the subway or buses. If the destination (目的地) is not far away, you can also walk ________ ride a bike.

    Call the hotline 12369. You can call the number for complaints and questions about environmental issues. It is run by China's Ministry of Environmental Protection. If you call the number, some officers can come and try to solve the issues, so please remember it.

Report and resist pollutant source. If you find any pollutant source, take a picture of it and post it on your social media accounts. Remember to add “@local environmental departments” on weibo. Payattention to factories that pollute the environment and don't buy products from them.

    Our environment will become better if everyone is concerned (关注) with the environment. This is what we need in the future. So everyone can do something to beat smog.

阅读理解。

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    Fraser Island is in Queensland, Australia, about 200 kilometers north of Brisbane. It is about 120 kilometers long and 240 kilometers wide. It is a very important island because it is completely made of sand. In fact, it is the largest sand island in the world. There is no airport on the island, but there is a long beach along the east coast. Planes arrive and leave from here.

    The sand makes unusual shapes. There are hills made of sand called sandblows. Nothing grows on them. They move one or two meters a year from the northwest towards the southeast of the island, getting bigger and bigger. At other places on the island, such as Rainbow Gorge, The Cathedrals and Red Canyon, the sandy rocks have different colors. Sometimes the rocks are so brown that they turn the sea brown, like coffee.

    Surprisingly, the sandy island has a lot of different plants and animals. There are dark forests—eucalyptus woods, beautiful flowers and over a hundred lakes. There are many kinds of birds, like owls and curlews. There are many animals there, too, such as crocodiles, flying foxes and wild dogs called dingoes.

    About 500,000 people visit the island every year to see the island's beauty and nature. People enjoy camping and hiking（徒步）there. Unluckily, the visitors create problems. They damage plants and frighten animals. Their sun cream（防晒霜）makes the water dirty. So it is necessary to manage the visitors. For example, people may not use motor boats or go fishing in the lakes, and they need official papers to drive there.

    The earth moves round the sun, and the moon goes round the earth. When our part（部分） of the earth turns to the sun, it is day, When our part of the earth turns away from the sun, it is night. The sun is much bigger than the moon. But sometimes the moon looks bigger than the sun, because it's much nearer to the earth. The sun is very bright. It gives a very strong light. The moon looks quite bright, too. But it doesn't give any light at all. The moon looks much bigger and brighter than the stars .But actually（事实上）, the stars are much bigger and brighter than the moon. They look smaller than the moon because they're much farther away from us.

    Many people know Shanghai's beautiful night view(景色), especially the colorful lights from the buildings. Light helps us see and makes the environment more beautiful. However, too much light becomes a kind of pollution but many of us pay little attention to this pollution or even ignore it. In fact, it causes a lot of problems. Light pollution can be almost as bad as carbon dioxide pollution.

    Too much light can do harm to our health. First, it can make us feel bad and we can't sleep well. Second, lights need electricity, and creating electricity will give off greenhouse gases. This affects the air and causes breathing problems. Third, study shows people living under bright light for long can have cancer more easily.

    Too much light may be even harmful to wild animals. Thousands of birds die from it each year. Some hit into the light buildings, because they can't see clearly in the strong light. Some birds sometimes lose their ways in the bright light Sea turtles(海龟) can't find the dark beaches to lay their eggs.

    To protect humans and wildlife, we should take measures to reduce the use of lights at night.

    What's a spacewalk? Any time an astronaut gets out of a spacecraft(航天器) while in space, it is called a spacewalk. Astronauts go on spacewalks for many reasons. For example, experiments can be placed on the outside of a spacecraft. This lets scientists learn how being in space affects(影响) different things. By going on spacewalks, astronauts can also fix things instead of bringing them back to the earth to fix.

    When astronauts go on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits, astronauts have the oxygen(氧气) they need to breathe and the water they need to drink. To keep the astronauts and the spacecraft safe, the astronauts must leave and go back to the spacecraft through a special door. When on a spacewalk, astronauts use safety  tethers to stay close to their spacecraft. Tethers are like ropes, connect the spacewalkers with the spacecraft. They keep astronauts from floating(漂浮) away into space. Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER is worn like a backpack. It helps an astronaut move around in space.

    How do astronauts train for spacewalks? One way is by going for a swim. Floating in space is a lot like floating in water. Astronauts practice spacewalks underwater in a huge special swimming pool. For every one hour they will spend on a spacewalk, astronauts need to train seven hours in the pool. Another way astronauts practice for a spacewalk is by using virtual reality(虚拟现实). It looks and feels just like a spacewalk.

    Today, only three countries have finished spacewalks independently. They are Russia, the United States and China. The first person to go on a spacewalk in the world was Alexei Leonov from Russia. Zhai Zhigang is the first Chinese astronaut to go on a spacewalk. The world record of spacewalks is held by Russian astronaut Anatoly Solovyev. He has been on 16 spacewalks and spent more than 82 hours outside in space.