In fact, if you line up clocks that each tell the time of a different city, and look closely at the second hand, you will notice that they are all slightly out of synch.

• 这就需要将许多显示各城市的时钟都摆放在面前。可是，仔细观察就可以发现，各个时钟的秒针走动都有些许的偏差。