Laughter is natural for people. We start to laugh at about four months of age. We start to laugh even1 we start to speak.

    Laughter connects us with others. We laugh more when we are with other people. It's difficult to pretend to laugh. Laughter is2. When people pretend to laugh, most people know it's not real.

   When do people laugh?

    Only 10 to 20 percent of laughter is about something3. Most laughter is about being friendly with other people. Most laughter says, "I don't want to4 with you. I want to be friendly with you." This kind of laughter brings people together.

    We often laugh when we feel nervous. In movies, there is often a joke at an exciting moment when everyone feels nervous. It is usually a(n)5 joke, but we laugh a lot. Our laughter helps us6.

   Why doesn't everyone laugh at the same joke?

    Not everyone has the same sense of7. Some people think a joke is funny, but other people don't think so. People have different ideas about what is funny.

    Our idea of what is funny changes with8. For young children, the world is new. They are interested in many things, so they laugh9. Teenagers often laugh to protect themselves. Adults laugh at themselves and other people with similar problems. They laugh at things that give them stress. Our10 for laughter change gradually.

Nowadays more and more people prefer to go fishing or hiking in the woods. Experiencing nature is {#blank#}1{#/blank#}, but when you're doing this, always keep yourself safe. It's important to remember several basic rules if you don't want to turn a pleasant outing into a {#blank#}2{#/blank#}.

First, be fully prepared for different weather. Before you set out, always get warm clothes and raincoats ready, just in case! This is especially true in the {#blank#}3{#/blank#} of travelling in the mountain areas. The weather is really {#blank#}4{#/blank#} in high mountains. Sometimes you can experience two or three seasons in one day.

Second, {#blank#}5{#/blank#} a map, a compass, and a flashlight in your bag. Even experienced travelers get lost. Before you start your trip, study the map to get familiar with the area you are going to. The flashlight is important if you do get lost. Many trips that start out in daylight will {#blank#}6{#/blank#} become nighttime adventures when people can't find their way.

Third, bring a first-aid kit and know how to use it. Small cuts can be more serious when there is no doctor {#blank#}7{#/blank#}.

Finally, tell people where you are going and when you plan to come back. That way, someone will go search for you if troubles {#blank#}8{#/blank#}. This will increase your chance of being found quickly.

At night, you fall asleep while listening to beautiful music. In the morning, the singing of birds outside wakes you up. You can enjoy all of these things because of one important organ(器官)— the ear.

You may wonder: how do our ears work? The ear has three different parts: the outer ear, the middle ear and the inner ear. The outer ear is the part you can see. It collects sound around you. The sound then travels down to the middle ear, the inner ear and then to your brain.

Your ears never stop working, even when you are asleep! Your ears continue hearing sounds, but your brain just ignores (忽略) them. That's why you may sometimes wake up suddenly in the middle of the night—your brain hears something, but you don't know what it is, since you are asleep.

But ears do more than hear. They help you keep your balance, too. In the inner ear, there are organs that are filled with liquid (液体) and covered in small hairs. When you move your head, the liquid and hairs move, too. They send messages to your brain about the position of your head.

More surprisingly, ears even help with tasting food. Of course, you don't actually taste food with your ears. But there are nerves (神经) running through the middle ear that connect the tongue (舌头) to the brain.

The ears are truly important. Everyone should make sure to protect their ears as well as they can.

Have you ever heard of water bears? They have lived on the earth for more than 500 million years, long before dinosaurs. Though called "bears", they look completely different from bears! The largest ones are only about 1.4 mm long. Each of their eight legs ends with a claw (爪) . They also have sharp mouths.

Some of the places they live may surprise you! They live deep down in the ocean. It's too dark to see well, and the water from up above is very heavy. But tiny water bears can survive in such a difficult environment. In space, there is no air, water or food. But water bears can live there! Astronauts took some water bears outside the spaceship. Surprisingly, most of them lived. Some even laid eggs. The eggs even hatched into healthy babies!

There is no rain in dry valleys of Antarctica for about two million years. But water bears can survive in such a place! How? First, they curl into a ball. Then they do nothing. They can stay in this way for many years! When they get wet again, they uncurl and start to move around. Sometimes wind or water moves away when they curl up in a ball.

Besides the places mentioned above, water bears also live around us, but we need some effort to find them. If we are careful and lucky enough, maybe we can find one.

 You must have heard of"city bu city"(meaning city or not city), an internet buzzword(流行语) created by foreign blogger Baobaoxiong. It's used to ask if a place feels like a big, fashionable city. 

 Millions of foreigners like Baobaoxiong are visiting China and posting their travel videos. The visa-free transit policy (过境免签政策) plays an important role in this trend(潮流). Travelers from 54 countries can stay in China for up to six days without a visa as long as they have a travel document(文件) and a connecting ticket(联运机票) to leave. 

 The visa-free transit policy started in 2013. Back then, it allowed travelers to stay for 72 hours in seven different big cities in China. Now, travelers can stay for 144 hours in 41 places 19 across 19 provincial areas . It has attracted more travelers to China . In the first three months of this year, 266 percent more foreigners came to China through visa-free policies compared with the same period last year, according to the National Immigration Administration of China (国家移民)管理局). 

△. Through this policy, more and more people get to see the real China

"This is the whole reason why we decided to come to China. We want to see exactly what it's like by ourselves, " said Irish YouTuber Luke in his online video. He thought Chengdu was unbelievably good, beautiful and modern totally different from what ho had heard about China from Western media.

 Yuyuantantian, a new media account(账号) under China Media Group, looked at 100 China travel videos made by foreigners. It found foreigners used to visit famous spots like the Forbidden City and the Great Wall. But now they prefer experiencing everyday activities like shopping at markets, riding shared bikes and joining square dancing in parks. These activities give foreigners a closer look at everyday life in China, said Yuyuantantian.