Fuel cells based on hydrogenburn cleanly, and are the subject of a serious research effort.
取材于氢气的燃料电池燃烧时无污染，并已成为一项重要研究的攻克对象。
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By comparison, getting a conventional internal-combustion engine to burnhydrogen instead of petrol is relatively easy.Even so, such efforts have also come to naught.
Like stars, brown dwarfs are capable of fusing a rare form of hydrogen called deuterium, but they are too lightweight to burn ordinary hydrogen and quickly run out of fuel.