经济学人下载:氢能--再看一眼玩具箱(1)

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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。