What was invented by Zhang Heng to detect a distant earthquake? A: star catalogue B: seismometer C: sundial D: compass

The author mentions all of the following ways to measure time EXCEPT ______. A: sundial B: electric clock C: hourglass D: mechanical clock

The most convincing evidence of establishing Dengfeng as the center of heaven and earth is ____. A: Zhongyue temple B: Songyang Academy C: the Zhougong Sundial Platform D: three Han Que gates