The air travel system is under great stress.

航空运输系统承受着巨大的压力。

Hundreds of passengers are crowding Australian airports on Monday as an open border travel system begins with New Zealand.

新西兰开始开放边境旅游系统，数百名旅客在星期一挤满了澳大利亚机场。

This atom may have traveled the entire solar system until it splashed on earth, long before reaching you.

这个原子可能已经穿越了整个太阳系， 直到它溅到地球上，远在到达你之前。