There are many wetlands in China and some of them have become the world's important wetlands. The Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are home for many different kinds of birds and animals. The world's largest Milu Deer Nature Reserve(自然保护区) is in them. More than700 milu deer live freely there. There are not many red—crowned cranes in the world, but every winter you can see some in the Red—crowned Cranes Nature Reserve in the Yellow Sea Wetlands.

    The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine, too. They are usually good places for wildlife. Offering food and home for some special kinds of animals and birds is not the only reason why we need to protect wetlands. Wetlands are important because they also prevent(阻止) flood(洪水). But some people want to change the wetlands to make more space for farms and buildings. This means there will be less and less space for wildlife.

    Luckily, more and more people are beginning to realize(意识到) the importance of wetlands and wildlife. Every year, on February 2^nd, many activities are held to tell people more about wetlands.

    What is a museum? A museum is a good place to keep old and beautiful things. A museum may be a place to learn about science and a place to find out about art or people or animals.

    What is inside a museum? Some museums have old cars and airplanes. Many museums have pictures and statues(雕塑). Others have rocks and old bones (骨头). One museum even has a real old street inside. It has shops and people's statues doing business. It looks so real that one might feel that he was back to the old time.

    Many cities have museums. Some very small towns have museums, too. Indianapolis has a children's museum. Children do not have to pay (付款) to get in. Children often go to the museum. They like to look at the dinosaur (恐龙)bones. They see a white bear ten feet tall.

    On Saturdays, Indianapolis children can hear talks about animals and trees. They see movies. They take hikes. They even learn to make things there.

    If you look at the top of your phone, you'll usually see a little symbol that says 3G or 4G.The "G" stands for the "generation (代)" of your mobile phone network. But these symbols will become things of the past after 5G networks fully arrive.

    On March 30, Shanghai vice-mayor Wu Qing made the first 5G video call on a Huawei Mate X smartphone, CGTN reported. Shanghai has also become the first city in China to start testing 5G networks.

    About 100 times faster than 4G networks, 5G will let people download and upload data faster than ever before. But 5G won't just bring faster mobile Internet. People can use it to do many other things as well.

    For example, 5G will help to make self-driving cars safer. Today's self-driving test cars have one problem-lag (延迟). When the car "sees" an obstacle (障碍物), it sends he information to a data center and receives instructions. However, it takes time to send and receive the information with this kind of lag, the cars might crash because they don't receive instructions in time. With 5G, this lag will be greatly lowered, making the cars safer according to CNN.

    5G could also be used to power the Internet of Things (IoT). This means a large online network that connects all things and people. Fast Internet speeds will be the key to developing this technology. The IoT could be used in a lot of ways. For example, with IoT, your fridge could automatically (自动地) place an order online for eggs when it finds that there are no eggs left.

    Is there intelligent (有智力的) life on other planets? For years, scientists said "no" or "we don't know". But today this is changing. Seth Shostak and Alexandra Barnett are astronomers (天文学家). They believe intelligent life exists (存在) somewhere in the universe. They also think we will soon contact these beings (人；生物).

    Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. "This is long enough for other planets to have intelligent life," say Shostak and Barnett. The second reason is size—the universe is huge. "Tools like the Hubble Telescope (哈勃望远镜) have shown that there are at least 100 billion galaxies," says Shostak. "And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar to Earth."

    In the past, it was hard to look for signs of intelligent life in the universe. But now, powerful telescopes (高倍望远镜) allow scientists to discover smaller planets. These planets might have intelligent life.

    Have beings from space already visited Earth? "Probably not," says Shostak. However, intelligent beings may contact us in other way, such as radio signals (信号). In fact, they may be trying to communicate with us now, but we don't have the right tools to receive their messages. However, this is changing. By 2025, we could make contact with other life forms in our universe and we might help each other.