There is a popular belief that goldfish only have a three-second memory. But a 15-year-old schoolboy from Adelaide has just finished an experiment（实验）to tell us that it is not true. He shows everybody that the goldfish is smarter than we think.

    “I don't believe that they had a three-second memory because animals need their memory, so they build up over time a knowledge of where the food is,” said Roy Stokes, a student at the Australian Science and Mathematics School.

    He did the experiment in small tank（鱼缸）of goldfish. “I decided to get a bit of red Logo and just feed them next to that. Every day I'd put it in and spread food around it.” He said.

    “At first they were a bit scared of it, but by the end of the three weeks, they were actually almost coming before I put the food in.”

    After leaving the fish alone for a week, Rory placed the red Logo block in the tank again.

    “They remembered perfectly well,” he said.

    “They actually had a time faster than the average of the three feeds before I left.”

    The goldfish showed that not only could they store information, they also had the ability to get it back as a later date.

    Culum Brown, a research fellow at Sydney's Macquarie University, has studied fish behavior for more than ten years.

    He says his studies of Australian native fish show fish were intelligent creatures that know how to avoid enemies and catch food like any other animal.

    “The thing that I really liked about Rory's experiment is he not only got that classical conditioning going but the fact that he could get them next just to that specific coloured market. I thought it was really good.” He said.

D

    The earth moves round the sun , and the moon moves round the earth . When our part of the earth faces the moon , it is night .

    The sun is much bigger than the moon . But sometimes the moon looks bigger than the sun , because it's much nearer to the earth

    The sun is very bright . It gives off very strong light . The moon looks quite bright , too. But it doesn't give off any light at all .

    The moon looks much bigger and brighter than the stars . But actually the stars are much bigger and brighter than the moon . They look smaller than the moon because they're much farther away from us .

    There is a lot of salt on the Earth, and it mixes very well with water.

There is some salt in all water. Water on the land runs into lakes and rivers. These rivers run into the seas and oceans. They carry a little salt with them. Some of the ocean water moves into the air and clouds. It evaporates. Salt cannot evaporate. It stays in the oceans.

    The water in the oceans has more salt than river water. There is about 3. 5% salt in the ocean water. Some seas have more salt than others.

    Some of the water leaves the lakes. It evaporates, but the salt cannot. These lakes are very salty. There are two famous lakes like this. They are the Dead Sea in the Middle East and the Great Salt Lake in Utah(犹他州）in the United States. They are much saltier than the Atlantic Ocean（大西洋）and the Pacific Ocean(太平洋）.

    Since the first person walked on the moon in 1969, technology has greatly helped space exploration. In recent years scientists have built a special robot to accompany astronauts on space missions (任务). Because this robot looks and moves like a person, scientists call it a humanoid robot. The latest model of the humanoid robot is known as R2, short for Robonaut 2.

    R2 was first launched into space on February 24, 2011. It was built by the National Aeronautics and Space Administration (NASA) and the car producer General Motors (GM).

    R2 weighs 330 pounds and costs $2.5 million to build. It has arms and a head- filled with vision equipment—but no legs. Its "brain", or computer, is in its stomach. R2's arms can hold 20 pounds. Each bendable finger has 5 pounds of grasping force. R2's hands are also skillful. Since its hands are shaped like human hands, R2 can use human tools to complete tasks traditionally performed by astronauts." Astronauts absolutely have their day packed from the minute they wake up until they go to bed. If Robonaut can provide just an hour's worth of relief to the astronauts doing something they don't want to do, that would make it worth it right there," says Nic Radford, the deputy project manager of R2.

    One advantage of working with R2 will be that ii can't complain about its work! Astronauts will also appreciate the fact that the robot can perform its duties without constant supervision (监管). R2 can be assigned a task and then checked on periodically. If R2 does not complete a task correctly, astronauts will be able to make minor adjustments to adapt (适应) the robot's behavior so that the task gets done right.

    R2 is still in the design stage of development, which means that scientists are frequently testing it and looking for ways to improve it. Right now, humanoid robots do not have the protective equipment needed to work outside the space station. As technology advances, humanoid robots will be able to help astronauts with dangerous tasks as well as routine ones.

    In the future, humanoid robots will be astronauts' eyes in space, going to places considered too difficult or unsafe for astronauts to explore. Some of them will be mounted on wheels to explore the surface of planets or asteroids (小行星). The robots will be able to send back videos and help astronauts gather information about the atmospheres of these places.

    One outcome of using these humanoid robots will be a greater understanding of the interaction between humans and robots. NASA engineers believe that when humans and robots combine forces and work together, the results will be better than what either could achieve alone. John Olson, a director at NASA headquarters in Washington, D.C, says that the project will allow us to go farther and achieve more than we can probably even imagine today.

    People don't like trash. Trash is smelly, dirty, ugly, broken and useless. That's why we throw it out. But everyone knows that trash influences our environment. It can pollute our land, water and air. So it's important to recycle our trash as much as possible.

    Some Americans were very interested in recycling and they were curious about what really happened to their trash. So, what did they do? They became detectives and decided to "Follow that trash!"

    They took some items out of their recycling bin and put electronic tags (标签) on them. The tags sent signals to a computer so people could follow their trash on its journey. They found that some trash only travelled a few kilometers but much of it went into landfills.

    Waste management companies in America think this detective work will be helpful to them. Dealing with waste is very expensive and this u trash tracking" will help them to become more useful. It will save their time and money.

    However, the trash detectives say it's also important to reduce the amount of trash we produce. After all, if we produce less waste, we won't have to worry about where it goes.