There seems never to have been a civilization(文明) without toys, but when and how they developed is unknown. They probably came about just to give children something to do.

      In the ancient world, as is today, most boys play with some kinds of toys and most girls with another. In societies where social roles are strictly determined, boys pattern their play after the activities of their fathers and girls after the tasks of their mothers. This is true because boys and girls are being prepared, even in play, to step into the roles and responsibilities of the adult world.

      What is remarkable about the history of toys is not so much how they changed over the centuries but how much they have remained the same. It is the universality of toys about their development in all parts of the world and their continuing to the present that is amazing. In Egypt, the Americas, China, Japan and among the Arctic peoples, generally the same kinds of toys appeared. Nearly every civilization had dolls, little weapons, toy soldiers, tiny animals and vehicles.

      Because toys can be generally regarded as a kind of art form, they have not been subject to (服从于) technological progress that characterizes inventions for adult use. The progress from the wheel to the oxcart to the automobile is a direct line of advancement. The progress from a rattle (拨浪鼓) used by a baby in 3,000 BC to one used by an infant today, however, is not characterized by inventiveness. Each rattle is the product of the artistic tastes of the times and subject to the limitations of materials then ready for use. (words: 285 ; time : 5ms)

       If you think that running marathons will help you live a long and healthy life, new research may come as a shock. According to a recent scientific study, people who do a very strenuous workout are as likely to die as people who do no exercise at all.

       Scientists in Denmark have been studying over 1,000 joggers and non­joggers for 12 years. The death rates from the sample group indicate that people who jog at a moderate pace two or three times a week for less than two and a half hours in total are least likely to die. The best speed to jog at was found to be about 5 miles per hour. The research suggests that people who jog more than three times a week or at higher speeds of over 7 mph die at the same rate as non­joggers. The scientists think that this is because strenuous exercise causes structural changes to the heart and arteries (动脉). Over time, this can cause serious injuries.

       Peter Schnohr, a researcher in Copenhagen, said, “If your goal is to decrease risk of death and improve life expectancy, jogging a few times a week at a moderate pace is a good strategy. Anything more is not just unnecessary, and it may be harmful.”

        The implications of this are that moderate forms of exercise such as tai chi, yoga and brisk walking may be better for us than“iron man” events, triathlons and long­distance running and cycling. According to Jacob Louis Marott, another researcher involved in the study, “You don't actually have to do that much to have a good impact on your health. And perhaps you shouldn't actually do too much.”