Only humans speak using words. But all kinds in the animal world can communicate in one way or another. Maybe you have heard about the way bees dance around to send messages to each other and the way dogs bark in different ways to give warnings, to be friendly or to be playful. But did you know about infrasonic communication used by elephants? This is how it works:

    Humans hear low sounds like thunder rumbling in the sky. But we don't hear sounds lower than this. However, animals such as elephants and hippos can hear much lower sounds than humans can. And what's more, they can make those low sounds as well, and they use them to communicate with each other. This is known as infrasound.

    The amazing thing about infrasound is that it travels over several kilometers. Higher-level sounds like the one people can hear, don't travel well through walls, leaves, trees and so on, which is why we can't hear sounds from more than 100 meters away. But infrasound is much stronger and things like grass and trees have no influence on it. Therefore, it can travel much further. Elephants can hear infrasonic calls from four kilometers away!

    There have been reports of people watching groups of elephants feeding or resting and then the elephants suddenly all stopped what they were doing for no reason at all. They obviously heard a warning call from a long way away, but the people didn't hear a sound. In places like a zoo or wildlife park where you can get nearer to animals, it is a bit easier to sense when infrasonic sounds are made. When you stand near mother elephants with their babies in a zoo, you may notice a slight rumbling in the air every few minutes—not loud or strong, but clearly noticed. This is infrasonic communication—the mother elephants “talking” to their babies.

    Everyone has got two personalities (性格)—the one that is shown to the world and the other that is secret and real. You don't show your secret personality when you're awake because you can control yourself, but when you're asleep, your sleeping position shows the real you. In a normal night, of course, you often change your sleeping positions. The important position that best shows your secret personality is the one that you go to sleep.

    If you go to sleep on your back, you're a very open person. You normally trust people and you are easily influenced by new ideas. You don't like to make people unhappy, so you never express your real feelings. You're quite shy and you aren't very confident.

    If you sleep on your stomach, you are a person who likes to keep secrets. You worry a lot and you're always easily becoming sad. You never want to change your ideas, but you are satisfied with your life the way it is. You usually live for today not for tomorrow.

    If you sleep on curled up (蜷缩) , you are probably a very nervous person. You have a low opinion of yourself and often protect yourself from being hurt, so you are very defensive. You're shy and you don't usually like meeting people. You like to be on your own.

    If you sleep on your side, you have usually got a well-balanced (平衡的) personality. You know your strengths and weaknesses. You're usually careful. You have a confident personality. You sometimes feel worried, but you don't often get unhappy. You always say what you think, even if it makes people angry.

The Taojinshan Greenway in Shenzhen has been open to citizens since July, 2019, Sitting at the west side of Shenzhen Reservoir, it is as long as 7.07 kilometres.

With plants along both sides and lakes lying at different sites, tourists can enjoy the beauty of nature all the way. If they are tired, they are free to take a rest at the 3 stops. Besides, five unused guard posts(岗亭) along the old route have remained. They are sightseeing platforms for visitors to feel the culture behind the place.

Of all its 13 scenic spots, 8 had AI helpers. From them, visitors can gain information on parking, tour guide services and more. The smart greenway, with free Wi-Fi, also provides environmental date, such as temperature, wind speed and air quality. What's more, it can give visitors warnings of coming extreme(极端的)weather and natural disasters, including rainstorms and typhoons that may hit Shenzhen.

"Started in the middle of 2015, the building process of the Taojinshan Greenway has taken good care of the wildlife and environment nearby," said Yang Shiming, an official in charge of the project.

The greenway is an example of construction

 (建筑) projects without doing harm to nature. It also shows the role that technology plays in building a smart greenway for more life convenience.

Every morning，many people in China do tai chi. It is popular with women and men. Tai chi is a kind of good exercise for old people. (A)它对身心都有好处。It is healthy and relaxing. Tai chi is from China. It is hundreds of years old. Tai chi is a "soft" martial art (武术). It is slow and calm (平静的). 

There are also "hard" martial arts. Shaolin kung fu，for example，which has a history of over 1，500 years，is a "hard" martial art. It is fast and dangerous (危险的). You have to be very healthy and strong to do "hard" martial arts. 

In Beijing，Master Li is teaching Shaolin kung fu to thirty young students. Three of the students come from abroad (国外). "Shaolin kung fu is difficult，" said Master Li. "(B)You have to practice every move many times. "

Sports like football and basketball are also popular in China. But martial arts like tai chi and kung fu are part of Chinese culture (文化) and history. 

Do you want a job in the holidays? Just go for it. First, you need to know what kind of job is suitable for your age and interest.

If you're 13 to 15

It seems that you can't work almost anywhere, but you're probably allowed to clean your neighbors' cars or walk their dogs. There is no lowest wage (工资）for children under 16. By law, you can't work more than 35 hours each week during school holidays. And you can't work before 7 am or after 7 pm.

If you're 16 to 17

The lowest wage for 16~17-year-old teenagers should be no less than seven dollars per hour. You can't work in a pub or bar, but you can work in many other places. By law, you can't work more than 40 hours each week.

What jobs are out there?

Obviously your choices are limited (限制) by the fact that you can only work during school holidays, but the following situations are fine.

At Christmas, most shops are short of hands, so you may find something to do there. In autumn, there's always fruit picking. It can be pretty hard work, but it pays really well.

If you're mad about football, you can choose to work in a sports shop or help out at a local football club. No matter how much you are paid, you are doing what you like.

The first computer came out in 1946. It was very1 and it worked slowly. Today computers are much smaller and2 faster. What can computers do? A writer said, "People can't live3 computers today."

The4 came a little later than computers. It is about 25 years5 than computers. But now it is almost6 . We use it to read books, do some shopping, play computer games or make friends. Many students use the Internet quite often. They7 online and maybe they never know these people. They don't know their8 names, ages and work. They are so interested in making the "unreal friends" that they can't put their hearts into9 . Many of them become poorer (更糟糕) in subjects than before10 that.

Computers and the Internet let us learn more about the world, but we should remember that they can't do anything.