氢气和氧气的混合气体共10g，点燃后恢复到室温，经测定还剩下氢气1g，混合气体中含有氢气　____ g，氧气　____ g．

我国素有“世界屋脊”之称的高原是（   ）

阅读下面这首诗，回答问题。
                                                                                                    过山农家
                                                                                               【唐】顾况
                                                                             板桥人渡泉声，茅檐日午鸡鸣。
                                                                             莫嗔焙茶烟暗，却喜晒谷天晴。                                                                    

实行“一国两制”科学构想的根本前提是（    ）