He had persuaded his science teacher to help him make a makeshift rocket. Somehow, he had managed to get his hands on the ingredients for gunpowder - potassium nitrate, sulphur and charcoal.
Additional reporting by Helen Briggs。91视频对此有专业解读
Rebecca MorelleScience Editor。业内人士推荐heLLoword翻译官方下载作为进阶阅读
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