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.

    Today, many endangered animals live in zoos. There, scientists work to keep each species(物种) alive. How do they do that? One way is by taking cells(细胞) from animals. Then the cells are frozen(冷冻). They can be used in the future to help animals reproduce.

    The San Diego Zoo has been freezing cells for 40 years. It's also called the Frozen Zoo. Now, the zoo is the biggest of its kind, with a large gene bank. It has cells from more than 1,000 species. One of the species is the northern white rhinoceros(犀牛).

    There are only five northern white rhinoceros alive in the world now. They are unable to have their children. Some scientists there want to use the bank's frozen cells to produce another northern white rhinoceros. They want to do this before the species dies out. That could happen by 2025.

    Can the zoo save the northern white rhinoceros? Other species have been saved successfully. So it's possible for the white rhinoceros too.

    Saving the white rhinoceros would be expensive. So some people don't think using frozen cells is the best thing to do. Some wonder whether it's worth spending millions of dollars on the species that nearly dies out. Some say scientists should work on the reasons why animals become endangered in the first place.

    Each year more than2,500 people die and 12,600 are injured in home fires just in the UnitedStates, with direct property(财产) lossbecause of home fires at about $7.3 billion every year. Every day Americansexperience tile horror(惨状) of fires, but most people don'tunderstand fires.

    To protect yourself, itis important to learn something about home fires.

    In less than 30 secondsa small flame can get completely out of control and turn into a major fire. Itonly takes minutes for thick black smoke to fill a house or for it to be inflames. Most deadly fires occur in the home when people are asleep, lf yourealize a fire, you won't have time to take valuables because the fire spreadstoo quickly and the smoke is too thick. The fire uses up the oxygen you needand produces smoke and poisonous(有毒的) gases that kill. Breathing even small amounts of smoke and toxicgases can make you tired and sleepy, and short of breath. The smoke can causeyou to be a deep sleeper before the flames reach your door. You may not wake upin time to escape.

    Room temperatures in afire can be 100 degrees at floor level and rise to 600 degrees at eye level.Breathing in this super-hot air will burn your lungs. It can melt clothes toyour skin. In five minutes, a mom can get so hot that everything in it startsto burn at once.

    Fires are bright atfirst, but quickly produce black smoke and complete darkness. If you wake up toa fire you may be blinded, confused about where you are or which direction you shouldgo in and unable to find your way around the home you've lived in for years.

    Only when we know thetrue nature of fires can we prepare our families and ourselves.

    There was a world's advanced robot exhibition in Moscow. Over 20 skilled robot performers from all over the world took part in the exhibition.

    The exhibition was opened by British-born Titan, a world-famous dancing robot that had performed together with artists. Besides its quick moves, the robot is also known for its stand-up comedy and beautiful voice.

    Robot Hespin, a life-sized humanoid robot can make others happy. The robot not only sings and dances but also acts as a museum guide. It's very impressive. It can even hold conversations with humans.

    Then there is Cubic, an ordinary boxy robot that has been created to make our lives easier. It can read the latest news, switch off lights, and order pizza. Cubic can hold basic conversations and tell jokes.

    South Korea's friendly robots not only dance but also clean floors. Germany's famous metal rock band performs wonderfully.

    Most of the robots seem to have some kinds of dancing skills. The organizers say that their main purpose is to create a meeting place or a global platform to enable the people of Russia to experience some of the world's most advanced robots.