There are a few ways to test how smart animals are.  method is to test memory. Scientists in Japan  a group of college students and a group of five-year-old chimps the numbers one to nine in different places on a computer screen. The test was to see  the groups could remember the position of the numbers in the correct order. Each time the chimps were  than the students. Why? Were the chimps special in a way? Did someone assist them? No, but the chimps probably had an important  They were young. As both humans and animals get older, their memory gets worse.

A Cloud of Hope and Danger

    In 2050, a small cloud floats through the air in a hospital operating room(手术室). In the room a patient, suffering from cancer, lies on a table. The cloud surrounds (包围) the patient, her body and filling her lungs (肺). The cloud is not smoke or steam. It is made of millions of microscopic robots called nano-robots(纳米机器人). These tiny robots move from cell(细胞) to cell in the body, destroying the cancer cells.

    Fighting cancer with nano-robots is only an idea today, scientists say that it would be possible in the future. Using nano-robots for good purposes such as fighting disease or repairing the environment may be the to many of today's problems.

    However, nano-robots could be a risk as well. Since nano-robots are so tiny, they will have to work in large teams of many thousands to 'many millions. For this reason, nano robots will have to be programmed to build . Scientists will not have the ability to build millions of nano-robots one by one.

    This to reproduce(复制)is making some scientists worried. What if something goes wrong in the programming? Quite a lot of crazy nan-orobots would be far than any disease. Some people think that if they get out of control, nan-orobots could destroy the Earth.

    What should be done? Should we continuenan-orobots or should we search for other methods? This is one of the many difficult that we have to make in the future.

My friend, Robert, has a twin sister named Amanda. Though they get along well, there  some things about Amanda and her friends that puzzle （困扰）Robert. He can't understand how girls can talk for so. For example, sometimes when he leaves home to play football, Amanda and her friend, Sharon, are sitting on the sofa, talking. When he comes back two and a half later, they're still staying in the same place, continuing the same conversation on the same topic. One day Robert was so curious(好奇的) that he asked Amanda what they talked about, but she , "We're best friends. We talk about almost everything— film stars, pop songs, recipes, everything!"

Boys and girls have different attitudes(态度) towards friendship. Friendships between girls are usually based on shared feelings and support (支持), but friendships between boys are based on shared activities or interests. A boy might be about sharing his feelings with his close friends. Aclosest friend, however, might be eager(急切的) to tell her about something that has happened in her life.

My friend, Robert, has a twin sister named Amanda. Though they get along well, there  some things about Amanda and her friends that puzzle （困扰）Robert. He can't understand how girls can talk for so. For example, sometimes when he leaves home to play football, Amanda and her friend, Sharon, are sitting on the sofa, talking. When he comes back two and a half later, they're still staying in the same place, continuing the same conversation on the same topic. One day Robert was so curious(好奇的) that he asked Amanda what they talked about, but she , "We're best friends. We talk about almost everything— film stars, pop songs, recipes, everything!"

Boys and girls have different attitudes(态度) towards friendship. Friendships between girls are usually based on shared feelings and support (支持), but friendships between boys are based on shared activities or interests. A boy might be about sharing his feelings with his close friends. Aclosest friend, however, might be eager(急切的) to tell her about something that has happened in her life.