经济学人下载:氢能--再看一眼玩具箱(1)

This forces it to feed frequently to replenish its energy.
这迫使它们必须经常进食来补充能量。

2.propel 推进

You will need some skills to propel you up that ladder of success.
你需要掌握一些促使自己往上爬升的技能。