Endangered dolphins are beautiful animals that needed to be saved. It may interest you to know there are about six different types of dolphins that are endangered. Many of them are river dolphins and they are very close to being lost forever if we do not take the time to care for them. The following is the reason why they are in danger.

    {#blank#}1{#/blank#}Dolphins can often get stuck(卡) in these nets and they may die. Another problem is the fact that many people and different countries will hunt for dolphins as food.

    {#blank#}2{#/blank#}When the oceans and rivers are polluted, it affects the very environment where these beautiful creatures are living. It may be important to also keep in mind that the dolphin is towards the top of the food chain.{#blank#}3{#/blank#} If these small animals are affected by the pollution as well, there really is no safe place for the dolphin to go.

    {#blank#}4{#/blank#}You can also pay attention to the land around you. Do not litter and stop if you do. Spend time on the weekend cleaning up trash in your area and recycle what you can. You play a large role in this whether you believe it or not. So, find out what your role is related to endangered dolphins and work towards a positive change.

    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.

    It is park at the bottom of the ocean. It's cold down there too. There's no air to breathe. The water pressure is high. There may be fishes that could hurt you. The deep sea can be an unpleasant place. But people are still fascinated by it, not just because of the amazing scenery. The seafloor might hold the secret to the beginning of life on Earth.

    Oceans cover more than two-thirds of our planet. Yet, we have explored just a small part of the underwater world. A new project is there to explore the ocean deeper. A new US machine can carry people down to as deep as 6,500 metres. It will take the place of an older machine called Alvin. The old one has been in use for 40 years, but it can only go down to 4,500 metres. Alvin played a key role in many important tasks. Alvin helped biologists collect worms, chemists gather rocks, and oceanographers (海洋学家) map the seafloor and take water sample (样本).

    But now it's about time for a new one. The new machine will be like Alvin. It'll also be about 27 feet long, about the size of a small school bus. The seating area inside will be small, about two metres wide. Like Alvin, it'll carry a pilot and two passengers. It will be able to move like Alvin does. It'll give passengers more chances to enjoy the view. Alvin has only three windows. The new one will have five. It will travel more than a mile an hour faster than Alvin. Getting to the bottom faster and moving around more quickly will allow researchers to make the most of their time underwater.

    Animals are natural resources that people have wasted all through our history. Animals have been killed for their fur and feathers, for food, for sports, and simply because they were in the way. Thousands of kinds of animals have disappeared from the Earth forever. Hundreds of animals are on the danger list today. About 170 kinds in the United States alone are considered in danger. Why should people care? Because we need animals, and because once they are gone, there will never be any more. Animals are more than just beautiful or interesting. They are more than just a source of food. Every animal has its place in the balance of nature. Destroying one kind of animal can create many problems. For example, when farmers killed large numbers of hawks, the farmers' stores of corn and grain were destroyed by rats and mice. Why? Because hawks eat rats and mice, with no hawks to keep down their numbers, the rats and mice multiplied quickly.

    Luckily, some people are working to help save the animals. Some groups raise money to let people know about the problem. And they try to get the governments to pass laws protecting animals in danger. Quite a few countries have passed laws. These laws forbid the killing of any animal or plant on the danger list. Slowly, the number of some animals in danger is growing.

    When a computer runs a group of programs, it can get very Cooling the computer can cost a lot. So some scientist's wonder what will happen if the heat from the computer can be used.

    Large Internet companies (公司) such as Google and Microsoft have thousands of computers. As these computers deal with information, they produce lots of heat, so they need huge cooling systems(系统). These systems send the heat into the air.

    A company in Holland (荷兰) thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-radiator.

    Boaz Loupe, the head of the company, says the e-radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer. So the users don't have to pay to cool their computers.

    Five homeowners in Holland are testing the heating system in their homes.

    "We pay for the computer using, so, in that way, homeowners get heating for free," Boaz says.

    Jan Visor is one of the homeowners. "If you use the computer more the e-radiator produces more heat," he says. "It cannot provide enough heat if you don't use your computer often. "But he is ready to try it. It's a great help for his family.

    The company says e-radiators can produce heat at a temperature of 55℃. It says the system can save its users about S 440 a year.

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

    On March 30, 2019, Shanghai vice mayor (副市长) Wu Qing made the first SG 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 (下载) and upload data (数据) faster than ever before. But 5G won't just bring faster mobile internet. People can use it for 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 this information to a data center and receives instructions (指令).

    However, it takes time to send and receive this information. With this kind of lag, the cars might hit each other because they don't receive instructions in time. With 5G, this lag will be greatly lowered (降低), making the cars safer, according to CNN. 5G could also be used to help the internet of things (IoT,物联网). IoT is a large online network that connects all things and people. Fast internet speed will be the key to developing this technology. The IoT could be used in a lot of ways. For example, with IoT, your refrigerator could automatically (自动地) place an order online for eggs when it finds that there are no eggs left inside.