Look at the centre circles of Diagram (图)A and Diagram B. Which of the centre circles looks larger? In fact, they are exactly the same size.
Then look at the picture on the right. What do you see? A vase? Or two faces？Does the picture change quickly from one to the other again and again? Maybe or maybe not, but you can never see them at the same time.

“What's happening? Is something wrong with my eyes?” You may wonder at what you see. Don't worry. Here is how it goes:
When we look at things, our eyes send messages to our brains and then our brains interpret（解读）the information. However, sometimes our brains interpret the received information in a wrong way. It seems that our eyes are playing a joke on us. This often happens and we call it “visual illusion(视觉错误)”.
Movie makers often make use of visual illusions. They make the objects around actors much smaller or bigger than usual. This makes us believe that the actors are much larger or smaller than they usually are. The movies Jurassic Parkand Honey I shrunk the kids just make use of visual illusions.

阅读下面短文，根据短文内容回答问题。

    For many smart phone users, especially young people, scanning QR Codes（二维码）has become a new and convenient life style these days. In fact, the QR Code was created in Japan in 1994, but until 11 years later, it was first used in China. It soon became popular around the country. The QR Code is much-loved because it provides a way to get to website more quickly. By scanning QR Codes, people can do lots of things, such as adding new friends, getting information, downloading Apps, shopping and so on. As for the shopping websites, there are usually more sales, including coupons（优惠券）for the phone users. The QR code is so common that people can scan them everywhere. We interviewed 100 people, and here are the results.

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    The earth moves round the sun , and the moon moves round the earth . When our part of the earth faces the moon , 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 off very strong light . The moon looks quite bright , too. But it doesn't give off any light at all .

    The moon looks much bigger and brighter than the stars . But actually the stars are much bigger and brighter than the moon . They look smaller than the moon because they're much farther away from us .

    When you look at the sky at night, the Moon looks bigger than the stars. Actually (实际上), the Moon is much smaller than the stars and the Sun. It's much smaller than the Earth. But the Moon is much closer to us than any star. That is why it looks so big. If you hold a coin close to your eyes, it looks big. If you look at it across the Moon, it looks small.

    The Moon moves around the Earth. It makes one trip in about four weeks. The Moon looks flat to us. But it is a round ball, like the Earth.

    People once thought the Moon had fire (火) on it. They thought the fire made it bright. Now we know the Moon is like a mirror. It gets its light from the Sun.

    Our sunlight comes from the Sun, too. What is the Sun? The Sun is a star. The stars we can see have their own light. There are many big stars we cannot see. Their light has burned out. Others are still bright, but they are so far away that we cannot see them. The Sun looks bigger and much brighter than other stars in Galaxy because it is the nearest of all stars. The Sun and the other stars we see are very hot, but the air around us saves us from the heat of the Sun.

    The Sun gives us light and warmth (温暖). It makes plants grow and turns leaves green. It makes life possible on the Earth. It is a life giving star.