When Chinese people find out that someone comes from London, they often ask, "London is a foggy city, isn't it?" British people who visit China often 1 say that London is not a foggy city at all! But if London is not foggy, 2 do so many people in China think it is? In fact, London used to be a foggy city, 3 it isn't any more.

    In London lots of its pollution came 4 factories, but a lot of it came from coal because people used it in their houses to keep warm during the winter. By the 1950s, London's air pollution had become so 5 that the government decided to do something to clean up the air. A new rule was made. It said that 6 was not allowed to burn coal in any British city. Just a few years 7 the air became much cleaner.

    Now many Chinese cities meet the same kind of 8 with air pollution that London met forty or fifty years ago. However, this problem is more difficult for Chinese cities to 9. First, more of the pollution comes from big factories than from coal that people use in their houses. If these factories are suddenly closed, lots of people 10 their jobs. Second, cleaner fuels(燃料) are quite expensive. However, the air in many cities is already slowly becoming cleaner, because the government and ordinary people are trying to make pollution less.

Mobike—it's a bike showing network where users search for a ride through an App. Mobike 1in shanghai at the end of last year.2 December 2016, Shanghai became 3 bike- share city in the world. And then Mobike recently expanded to Beijing, Guangzhou and Shenzhen. They are becoming 4 popular, especially among white -collar workers during rush hours. For that reason, a large number of bikes5in the streets. The bike ride's record has reached about twenty6on a single day .

    Mobike is7convenient that the users can find and leave bikes wherever they'd like. The users8 have the company's mobile's APP just need to use their phones 9 the QR code (二维码) on the bike, and then unlock the bike to begin the timer on the Uber-esque .Besides Mobike doesn't use a parking station in the street.Instead, users can10bikes anywhere with the app-controlled smart lock.11 it also means that users sometimes leave them in a bad place where it's hard for12users to find them. To deal with this problem, the founder of Mobike and her team 13on a points-based system to punish unruly rides.

    Sharing  bikes is made to reduce the pressure of traffic.14 it can run well, and the price is kept low, it may be a great15 to protect the environment .

    The universe is really mystical(神秘的). Scientists have done lots of study about it but there is still much they haven't discovered.

    Scientists think that there 1 life on the earth for many many years. However, we haven't found life on any other planets 2

    There are eight planets going around the sun. The earth is one of them. There are humans, animals, plants and many other kinds of life on the earth. There is water and air, too. And compared to the other planets, the earth is not too 3 or too cold. None of seven other planets has av. environment like that of the earth.

    The sun and its planets are called the solar system, and our solar system is a small part of a 4 larger group of stars and planets, called the Galaxy or the Milky Way. There are 5 stars in the Galaxy, and our sun is only one of them.

    Scientists have also discovered many other galaxies in the universe. Their light has to travel for many years to reach us. So 6 is the universe? It is impossible to imagine.

    Scientists have sent spaceship to the planet Mars 7photos. They have even sent spaceships to travel outside 8 . However, no spaceship has traveled 9 to reach other stars in our Galaxy.

    When we see stars twinkling(闪耀) in the sky at night, we may think a lot:10 so many stars in the universe, is there life out there in space? If there is life on other planets, what life will be like there? What transports do they use to travel? Why don't they visit us? We do not know the answers…

    Natural resources that we use are things that come from the Earth.

    Our natural resources are limited(有限的）. This means that they will not1 forever. Some are renewable, like when you plant a new tree when you2 one down. Others are not renewable, like when you dig coal(煤）out of the3. Once it is used, it is gone.

    People realize the4 that the Earth's natural resources are limited, and people can do things to help conserve(节约）those resources. 5 you try to conserve a natural resource, you try to use less of it so it does not run out so 6One way that people conserve fuel, like gasoline, is by riding a bicycle or walking when the 7 is short instead of driving everywhere.

    Water is a very important natural resource because we all need it to stay 8. We can conserve water9 making sure that the pipes and taps do not leak(漏）. We can also make10 choices to conserve water, like only using the dishwasher or washing machine when they are full. Everyone can make contribution to protecting natural resources.

    It says that bats (蝙蝠) are almost blind (瞎的). Do you know 1 the bat finds the way? In fact (事实上), bats find their ways 2 the help of their ears. Bats make a 3 that we can't hear at all. They cry when they fly and the echoes (回声) of these cries come back to their 4. In this way they can know where they should go. Bats fly out in the 5. In the daytime, they just stay together in their homes.

    When the evening comes, they begin to 6 and look for 7. The next morning, they come back from work to sleep 8 the evening. Some people 9 that bats are bad animals. In fact, they are very 10. They catch and eat pests (害虫). This is very good for people.