题目

阅读理解 It was a village in India. The people were poor. However, they were not unhappy. After all, their forefathers had lived in the same way for centuries. Then one day, some visitors from the city arrived. They told the villagers there were some people elsewhere who liked to eat frog's legs. However, they did not have enough frogs of their own, and so they wanted to buy frogs from other place. This seemed like money for nothing. There were millions of frogs in the fields around, and they were no use to the villagers. All they had to do was catch them. Agreement was reached, and the ch下列说法正确的是（　　）A．省力的机械一定费距离，不省功B．省距离的机械一定省力，但不省功C．省力的机械可以省功，但一定费距离D．省距离的机械一定费力，但可以省功