B Energy-saving Finns invented the first ice skate more than 5,000 years ago, as a practical method of transport to make getting across frozen lakes less of a struggle. The earliest skates would have been blades made from bones and are one of the oldest means of transport ever discovered —they may even have been essential survival tools. Researchers at Manchester Metropolitan University have calculated that ice skates would have saved energy by 10 percent, and suggest that they were developed for practical use and were not used for recreation, as they are today. They think the most likely birthplace of skating is southern Finland, where there are many icy lakes. The scientists have put their theory to the test and made replica（复制品） skates modeled after examples held at the British Museum and the Fitzwilliam Museum in Cambridge. Volunteers on ice rinks in the Alps had their heart rates, oxygen intake and skating speeds measured while they skated with the replica skates. From this experiment, re-searchers were able to calculate energy consumption and the efficiency of their skating. They discovered that skating over the land in ancient Fin-land would have saved 10 percent of people’s energy. The result is based on the fact that Finland has the highest concentration of lakes in the world. The ancient Finnish people could benefit more than others from developing this tool for transport. In a time and environment in which the balance between energy taken from food and energy required to live was crucial; the least cost of energy might have helped humans survive in extreme conditions. 45. The first ice skate invented by the Finns was used for _____. A. recreation                           B. transportation across lakes C. saving energy                       D. sports 46. The birthplace of skating might be southern Finland because _____. A. there are many icy lakes there B. people need more oxygen to breathe in there C. people feel tired easily there D. transportation there is more difficult 47. Scientists have experimented with replica skates and found that with those skates the ancient Finnish people would have _____. A. crossed a lot of lakes B. saved 10 percent of energy when crossing the lakes C. climbed the Alps easily D. otherwise wasted a lot of food and energy 48. It can be inferred from the story that _____. A. the Finnish people were clever enough to invent the practical skates B. there were a lot of lakes in ancient Finland C. the living conditions were very hard for the ancient Finnish people D. it was very cold in ancient times in Finland