Do you want to live another 100 years or more? Some experts say that scientific advances will one day enable humans to last tens of years beyond what is now seen as the natural limit of the human life span.

    “I think we are knocking at the door of immortality(永生),” said Michael Zeya, a Montclair State University business professor and author of two books on the future. “I think by 2075 we will see it and that's a conservative estimate(保守的估计).”

    At the conference in San Francisco, Donald Luria, a professor at New Jersey Medical School in Newark said advances in using genes as well as nanotechnology(纳米技术) make it likely that humans will live in the future beyond what has been possible in the past. “There is a great push so that people can live from 120 to 180 years,” he said. “Some have suggested that there is no limit and that people could live to 200 or 300 or 500 years.”

    However, many scientists who study in ageing are doubtful about it and say the human body is just not designed to last past about 120 years. Even with healthier lifestyles and less disease, they say failure of the brain and organs will finally lead all humans to death.

    Scientists also differ on what kind of life the super aged might live. “It remains to be seen if you pass 120, you know; could you be healthy enough to have good quality of life?” said Leonard Pooh, director of the University of Georgia Gerontology Centre. “At present people who could get to that point are not in good health at all.”

    What do you think the future will be like? Here are some answers from some students.

    Mary: Everyone will have a computer at home. There will also be many machines in the future. Then people will work only two or three days in a week.

    Jack: The weather in the future will be very hot. People can't live on the earth. They will have to look for (寻找) another planet to live on.

    Linda: I think the life in the future will be nice. There will be a lot of flowers and trees. And cities will look like parks.

    Henry: Every family will have a family doctor, so people will be seldom ill (很少生病) They will live to 120 years old.

    It is a question that has confused parents for many years: why do children refuse to eat greens?

    Now, two American experts believe they have the answer.

    After studying dozens of babies as they played with various objects, the researchers noted that they were far more unwilling to touch plants than other things. They believe this is because evolution (生物进化) has biologically made children be wary of plants.

    Due to susceptibility (敏感性) to illness or injury in the early years of life, the body has designed an inner defence mechanism (内部保护机制) that limits a child' s contact with plants, they think. The researchers believe this is why children turn their noses up when faced with a plate of broad beans.

    The findings are published in a paper by Dr Annie E Wertz and Dr Karen Wynn, both psychologists at Yale University.

    They wrote, "Throughout human evolution... plants have been important in human's life. Yet, for all of these benefits, plants have always caused very real dangers."

    "Plants produce toxins (毒素) as defences that can be harmful, or even deadly. Some plants also produce physical defences, such as thorns（荆棘）can damage tissues (组织) and cause effects over the whole body."

    They added, "We predicted that babies may have behavioural strategies that reduce dangers caused by plants."

    To test their theory, the researchers studied how children aged eight to 18 months old reacted when presented with a variety of objects. It took much longer for children to grab plants; objects that were pretended to look like plants also caused a slow response time.

    For parents attempting to spoon some peas into the mouth of their child, this finding should come as welcome relief.

    1970 was World Conservation(保护) Year. The United Nations wanted everyone to know that the world was in danger. They hoped something could be" done.

    Here is one example of the problem. At one time there were 1,300 kinds of plants, trees and flowers in Holland(荷兰), but now only 866 are left. The others have been destroyed (毁灭) by modern people and their science. We are polluting earth, air, water and everything around us. We can't live without these things. If things go on like this, we shall destroy ourselves.

    What will happen in the future? Perhaps it's more important to ask "What must we do?". More and more young people have known this. Many of them are helping to save our earth. For example, they plant trees. In a small town in the United States a large group of girls cleaned the banks of 11 kilometres of their river. Young people may hear about conservation through a song called "No one's going to change our world". It was made by Cliff Gichard and other singers. The money from it will help to conserve tigers, elephants and pandas on the earth.