【正确答案】Measuring time by the flow of water has disadvantages. By and by, people invented time-measuring devices with water as the driving force for its mechanical system. In 117 BC, Zhang Heng manufactured the Water-driven Celestial Globe, a large, astronomical, time-measuring apparatus that had the primitive function of a mechanical time measurer. Through the later dynasties, many apparatus with attached time-measuring devices were produced. In the Song Dynasty (AD 960—1279), Su Song’s Water-driven Celestial Observatory marked a new height of mechanical time-measuring instruments. The time-measuring mechanism had wooden puppets to beat a drum to announce a quarter, to ring a hand-bell to tell time every other hour and so on. These mixtures of astronomical instruments and time-measuring devices cannot be seen as independent time measurers. By the 1360s, China’s mechanical time-measuring devices had been separated from astronomical instruments and became independent. They not only had drive systems with gears, but escapements as well. If the Chinese people had made one more step, they would have produced clocks in the contemporary sense. Unfortunately, China failed to do this, and ultimately had to introduce mechanical clocks from the West. —Excerpts from Chinese Culture, 2000 (1)