题目

Every day we use money to buy what we want. But have you ever really noticed the bill (钞票) in your hand? There are different pictures on both sides of banknotes (纸币) and interesting stories behind them. Most banknotes have famous people on the front, such as a country’s leader or a great scientist, while on the back of the paper note there are usually some well-known scenes or national buildings. The latest editions of Chinese banknotes use the picture of Mao Zedong, founding father of the People’s Republic of China, on the front of all yuan bills. However, the backs of the b第一次通过实验比较准确地测出万有引力常量的科学家和所做的实验是： Ａ．牛顿地月实验　           Ｂ．伽利略斜塔实验　 Ｃ．牛顿扭秤实验　　         Ｄ．卡文迪许扭秤实验