A-A+ Helium is not flammable and next to hydrogen 2022-08-05 16:59:50 问答库 阅读 170 次 问题详情 Helium is not flammable and, next to hydrogen, is ______A.known the lightest gasB.lightest the known gasC.the lightest gas knownD.the known gas lightest请帮忙给出正确答案和分析,谢谢! 参考答案 正确答案:C