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The sun shines again after rain, and you see red, orange, yellow, green, blue, indigo,and purple light in the sky—a rainbow.

Refraction in Action

Sunlight has all the colors of the rainbow, but some go faster when sunlight passes through water. From top to bottom are the faster ones to the slower. Red is the fastest and purple is the slowest.

As light enters water, it refracts. Red, traveling fastest, is refracted (使折射) least. Orange is refracted a little more, and so on. Different colors are separated in this way and that’s what you need to get a rainbow.

How to See a Rainbow

Stand with your back to the sun and search the sky, because a rainbow appears opposite the sun. If the sun is too high, no rainbow can appear. Look at your shadow, the dark shape your body makes on the ground. If it’s taller than you, you have a good chance of seeing a rainbow. The longer your shadow is, the bigger the rainbow.

Guess the Weather

If a rainbow appears in the morning, that means the rainbow is in the west, which is where the rain is. Weather usually moves from west to east, so the rain is coming your way. If it’s in the afternoon, things will be different. Here’s a saying:

Rainbow in the morning, shepherd (牧羊人)’s warning.

Rainbow at night, shepherd’s delight.

See Two at Once

Look for a second rainbow after you see one, but it’s hard to see. The main rainbow has red on top and purple on bottom, but the secondary has red on bottom and purple on top.

Unseen Rainbow Parts

Sunlight has infrared radiation (红外线), which we can’t see. Still, infrared radiation gets refracted by raindrops, and lies above the main rainbow’s red light. Ultraviolet radiation (紫外线) is also part of a rainbow. It’s just below purple.

Achoo! We all sneeze sometimes. Sneezing is a reflex (反射作用) that your body does without control. That means you cannot make yourself sneeze or stop one once it has started. When you sneeze, your body is trying to get rid of bad things in your nose, such as germs. You have a lot of germs when you have a cold, so you sneeze a lot more. You might also sneeze when you smell pepper (胡椒)!

Inside your nose, there are hundreds of tiny hairs. These hairs filter the air you breathe. Sometimes dust (粉尘) find their way through these hairs and cause trouble to your nasal passages (鼻腔). The nerves in your nose tell your brain that something is hurting your body.

Your brain, lungs, nose, mouth, and the muscles (肌肉) of your upper body work together to blow away the germs with a sneeze. When you sneeze, germs from your nose get blown into the air.

It is very important to wash your hands after you sneeze into them, especially during cold and flu season.

Do you ever sneeze when you walk into bright sunlight? Some people say that happens to them often. Scientists believe the UV rays of the sun irritate (刺激) the nose of these people so they sneeze.

If someone nearby sneezes,remember to tell them “Gesundheit!” That is a funny-looking word which is pronounced “gezz-oont-hite.” It is the German word that wishes someone good health after sneezing.

5 . When the flu (流感) hits you, it often seems to be most severe (严重) at night. You might have a cough, a blocked nose, or a sore throat that just won’t let you sleep. Have you ever thought about why the flu feels so bad at night?

One reason has to do with your body’s daily clock. At night, when you’re trying to rest, certain small parts in your body that fight off sickness become more active. They’re working hard to get rid of the sickness, but this can make you feel worse. It’s like your body is having a silent battle with the flu, and you feel more coughs, stuffy nose, and aches because of it.

Another factor is how lying down affects you. When you’re up and moving around, the force that pulls everything down helps mucus (粘液) clear away. But in bed, mucus collects in the back of your throat, causing that itchy (痒的) feeling that makes you cough. This is called nose drip after lying down and can be really annoying when you’re trying to sleep.

So what can you do about it? Drinking lots of water throughout the day can help by making mucus thinner and easier to clear. Before bed, a hot shower might also help open up your nose. And when it’s time to lie down, try lifting your head up with a few extra pillows (枕头). This can prevent mucus from building up in your throat and help you breathe more easily.

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6 . Hunger is more than the feeling you get when you miss an after-school snack. It’s a world problem that influences one in nine people around the world. Every year, more than a quarter of a million people die of hunger. That’s more than the amount of people who die of some common diseases like hepatitis (肝炎). It’s important that we eliminate this deadly problem.

One of the biggest problems with hunger is that it creates a circle of poverty (贫穷) and more hunger. People who can’t afford to buy nutritious (有营养的) food often become weak and ill. They are unable to work and can’t support their families. Often, children must work in fields or factories to earn money for food. For boys and girls who do attend school, hunger can make it difficult for them to pay attention and learn. Poor health and education make it harder for these children to get jobs in the future, which makes the circle of hunger continue.

Genetically modified (GM) crops (转基因作物) have helped scientists fight the hunger problem. These crops have helped provide more food and help farmers make more money. However, some people don’t trust these crops. They worry the food is unsafe. Still, there is a lot we do not know about GM food. Will GM food make people sick? We do not know. It’s better to do more tests before we widely use it.

Hunger isn’t an easy problem to solve, but change is possible. There is more food than ever before, and the number of people living with hunger has gone down. If we can work together and continue to find better ways to get food to the people who need it, we will end world hunger in the future.

Flying kites is a normal way for people to relax. You can see many children and parents fly kites in the park     1     spring. In fact, kites were not invented to relax at first. It’s said     2     kites were invented by a famous Chinese philosopher (哲学家). Historical records show that kites had several names, such as Zhiyuan in the north in ancient China. All of them     3     borrowed from the names of birds. During the late Tang Dynasty, some people put music strings (琴弦) on kites, and they produced a sound like the Chinese zither (古筝) ,     4     people called them “fengzheng”. The name is still used today.

During the Song Dynasty, kites became toys, and kite making turned into a kind of traditional folk art. Weifang is famous     5     its kite making and flying customs. Each year, the Weifang International Kite Festival is held in April, and kite lovers from all over the world take part in it.

Have you ever eaten pancakes with maple syrups? They are delicious! Canada is famous for its maple syrup. The maple leaf is even on the Canadian flag. Maple syrup comes from the maple tree and around 70% of the maple syrup in the world comes from Canada. And 90% of that comes from Quebec, in the east of the country.

First, sap (汁液) is collected from the maple trees. A tap is put into the tree to collect the sap. The bucket in the picture: above is full of sap. This takes place during spring—from early March to late April. Sap can be collected from larger trees up to three times during spring.

Next, the sap is taken to a large storage tank (存储罐). The sap travels through pipes (管子) to sugar house. This is where the sap is made into syrup. The sap is boiled to make it into syrup. As the sap boils, it becomes thicker and sweeter. About 40 kilos of sap makes about one kilo of syrup. Once the syrup is ready, it is put into bottles or cans and sent to shops and businesses.

You can use maple syrup in many different ways. You can put it on pancakes, ice-cream or oatmeal. It tastes great on salad with a little lemon juice. You can also cook with maple syrup. You can put it on vegetables, pork or chicken before you cook them. Some people like to use it in tea and coffee instead of sugar. In fact, maple syrup is a little healthier than sugar. It has some different minerals (矿物质) in it, so you don’t have to feel too bad about eating this sweet treat!