If an event runs on, it continues for longer than expected.

The game/speech/discussion ran on for hours. 这场比赛／演讲／讨论持续了数小时。

If time runs on, it seems to pass quickly.

Time's running on - let's get this job finished soon! 时间过得太快了——我们还是尽快把这工作做完吧！

If a machine runs on a particular type or supply of power, it uses that power to work.

Some calculators run on solar power. 一些计算器利用太阳能来工作。