I can see many electron cloud suddenly vanish on the originally track, then jump to the higher energy leveltrack.
我可以看到很多电子云突然间在自己原本的轨道上消失，然后跃迁到更高能级的轨道上。
2
A train travels from a station to the next along a leveltrack, it is necessary to finish the journey within a given time and to minimise the energy consumption.
火车沿水平轨道从一站运行到下一站，要求在给定的时间内完成该行程并使能耗最小。
3
Attractive in the low leveltrack, propose full discount strategy, starting from the beginning of a discount ticket sales, model building, find the best discounts.