【推荐1】If someone asks you, “    1    ” I think you will answer “Blue”. I’m afraid that you will be wrong.     2     It looks blue because we are looking at the blue sunlight. The sunlight is shining on little bits of dust (灰尘) in the air.

    3     I’m sure that you have asked this question, too. We know that there is air all around the world, but we couldn’t fly very high because as we go high, the air gets thinner. If we go far enough away from the Earth, we find there is no air.

Maybe we can answer some questions now. What is the sky? Where is it? It is all around the world.     4     In space, there is nothing, but only the Sun, the Moon, the Earth and all the other stars.

【推荐1】Watermelons used to come from Africa where it is hot all year. They grow best in warm temperatures. But could you grow one at the South Pole, the coldest place on Earth? Scientists say yes.

Russian scientists tried an experiment (实验) to grow a watermelon. They work at a Russian research station at the South Pole,though watermelons usually don’t grow in such cold places. So the scientists had to use a greenhouse where they can control the temperature, light and water in it.

The team chose two kinds of watermelons to grow. The fruits are known for their delicious taste and they grow more quickly than other kinds. The scientists used the soil substitute (土壤替代物) instead of the normal soil. Special lighting acted as sunlight. There were no butterflies so scientists had to pollinate (授粉) the plants themselves. Only in this way can the flowers become fruits.

The scientists watched the seedlings grow. It took them 103 days to get watermelons to eat. They got eight watermelons and each weighted about 1 kilogram. The experiment was so successful that it shows watermelons can be grown in the coldest place on the planet.

One scientist said they were all glad. It was like a taste of summer. Watching the seedlings grow made the scientists happy. In fact, the station has grown plants before. Scientists grew vegetables such as cabbage in 2020. And they aren’t stopping with watermelons. Next, they plan to farm other fruits such as blackberries, blueberries and strawberries.

【推荐2】On November 14, 2023, the International Civil Aviation Organization (ICAO) (国际民用航空组织) officially recognized China’s Bei Dou Satellite Navigation (卫星导航) System (BDS) as the world level. This makes it one of four global (全球的) satellite navigation systems, along with the United States’ GPS, Russia’s GLONASS and the European Union’s Galileo.

China started to develop the BDS in 1994. The system came into use in 2000. After 12 years of work, it began serving the Asia-Pacific region. In 2020, with the global use of BDS-3. China has improved the system to provide users with more correct positioning services, making it a valuable tool for more industries (行业), including transportation, agriculture (农业), and surveying (测量).

Now with 59 satellites in its network, the BDS has served more than 1.5 billion users across the world. Most mobile apps providing maps navigation and shopping services in China already support the BDS. China’s satellite navigation industry is growing fast. Its value reached more than 500 billion yuan in 2022. That number is expected to double by 2025. In the first half year of 2023, there were about 13.4 million new BDS devices (设备). Nearly 60% were used in transport systems. The rest were used in communication and agriculture. The former made up about 28% and the latter 12%.

As BDS gets more popular, it is expected to play an increasingly important role in global navigation and positioning services.

China is the hometown of kites. Making and flying kites is one of the Chinese ancient folk skills. Kites are also an important part of the Chinese culture.

Kites were invented by the Chinese during the Spring and Autumn Period, having a history of over 2,000 years. It is said that Modi, made a wood bird after the work of three years. This might be the earliest kite in human history. Then Lu Ban made changes to the kite of Modi by using bamboos. Some folk custom experts told that ancestors invented kites mainly to memorize their family members and friends who have died. So on the Qingming Festival people would make and fly kites, hoping that their sadness could be passed to the dead through the kites. In the Northern and Southern Dynasties, paper has been used to make kites because of the paper-making. In Song Dynasty, flying kites became a favorite outdoor sport of the people. According to researchers, and they were not spread to Europe until the thirteenth or fourteenth century.

Flying kites needs skills. The controlling string (绳) and the pulling force are decided by the size and the shape of the kites, the environment and the wind. Right wind often blows in spring, flying kites should avoid cloudy days and rainy days. Safety is also an important consideration. Flying kites should be done on an open ground and it is not wise to fly kites in dangerous places such as water side and tops of buildings.

【推荐1】Computers can help us in many ways, but they cannot think or do things on their own.     1     They cannot come up with any new information, but they can save much time and work. For example, all the information and office files can be stored in a computer’s “memory”.

The first computers were huge and expensive. They filled up almost the whole floor of large offices.     2    . They invented chips(芯片) which made it possible to store more information in less space.

    3     They can just be placed on top of an ordinary writing table. They can even be carried from place to place easily. Computers are not only used in offices by companies, but are used at homes by families who can afford them.

    4     A robot can do the same work as a person for 24 hours without complaining or getting tired.     5     As computers become more and more common in businesses and factories, people fear that one day computers and computer-controlled robots will put human workers out of work.

【推荐2】Have you ever wondered why the letters on a keyboard are not in the “ABC” order?

The keyboard we use every day is called the QWERTY keyboard layout (布局) . Q, W, E, R, T, Y are the first six letters on this layout, starting from the top left.     1     .

The first manual typewriter (手动打字机), with a keyboard which looked like a piano, was invented in the 19th century.     2    . However, people later, found that as the typing speed became faster, some keys failed to come back to their places quickly. As a result, they got jammed (卡住) very easily.     3     To solve this problem, the QWERTY keyboard was developed. It placed keys in such a way that the most used letters were spaced out so that the keys were more likely to work freely.

    4    . With the arrival of the computer, the typists in offices were the same people who were to now operate computers. This meant the typists had to be trained to use the new device.     5     it was easier to design the keyboards following the layout of typewriters, which was the QWERTY layout, and this continues even today.

【推荐3】We all know that many inventions have changed our life a lot. They play important roles in our daily life. Here are some interesting inventions.

Since the great success of cloning(克隆)the sheep Dolly, the cloning of human beings is no longer a fictional（虚构的）story but can be proved to be medically possible.     1     I just want to say: NO! NEVER!

    2     For example, they believe that if we could clone a new Einstein, we would make more progress on physics; and if we could get a new Shakespeare, we would enjoy more classic literary works and ... But how can we make sure that another Hitler could not be brought back to life “thanks to” cloning? Moreover, can we give birth to a baby who exactly shares your grand grandpa’s genes? We would be confused by that relationship.     3    

Some scientists believe that we can get the organs(器官)we need to save people’s life from the cloned persons. But is it unfair to them? Even if they are not created by nature but by technology, they are a kind of life.     4     I do not suppose this action is humane.

    5     It is against the natural law. Life should be a cycle from birth to death and then rebirth and re-death. Every round of change can produce more varieties of genes. Therefore, our human beings can live rather than copying ourselves repeatedly, which I believe would lead to the final retrogression(退化)of human species.