（6分）据报纸登载，深圳某商场开业庆典时，店外挂的氢气球因人群拥挤而被挤破，遇上点燃的香烟，引起爆炸，并引发邻近一串氢气球爆炸。迅速掠过的火苗烧了一些顾客的头发，并浅度灼伤20多人的皮肤。请简要回答：
（1）以上事实说明氢气具有什么化学性质 。
（2）新的方案是：采用一种安全气体——氦气，作为大型升空气球的气体，由此推测氦气应具有的性质是① ②
（1） 易燃或可燃性，化学性质较活泼 。
（2）① 密度比空气小 ② 化学性质稳定
分析：物质的结构决定物质的性质，物质的性质决定物质的用途．
解答：解：
（1）由题意可知：氢气具有可燃性．故答案为：可燃性；
（2）氦气属于稀有气体，化学性质很稳定，并且氦气的密度比空气小．
故答案为：
①密度比空气小 ②化学性质稳定．
点评：本题主要考查了物质的性质和用途等方面的知识，同时明确物质的性质决定用途
I was sitting in the surgical waiting area at the hospital waiting for word of my wife's operation. The small room was filled with other families and friends who were 36 waiting to hear how their loved ones were doing. There was a young boy sitting quietly in the__37__.He held a small box of__38__in one hand and a tablet( 写字板)in the other. Every so often he'd place the tablet on his lap and draw something. As the hours passed I began to see the room almost__39__.And there was a strange silence. “Daddy，when is Mommy going home？”the young boy asked，breaking the__40__. “Tomorrow，”his father replied. The boy picked up his crayons and__41__something on the tablet. I _42__him as he moved his feet back and forth，looking up at the ceiling and then toward the sunshine－filled window.“When's__43__，Daddy？”he asked. His father__44__him over to sit by him. “Come，_45__here next to me，”he said with a gentle tone in his voice. __46__his things，the little boy walked slowly to his father's side from the corner. The man_47__out and held his son by his shoulders. “There are three days in life. Yesterday，today and tomorrow. One is over and done，one we live in，the other we__48__.We can't live in yesterday，but if we are happy enough today，we will be even happier tomorrow，”he said in an attempt to__49__the boy. The little boy looked at him for a moment and said，“If Mommy is going home tomorrow，I'll be__50__. So，I want it to be tomorrow already, Daddy.” Now hanging on every word of this__51__，I leaned forward to hear his response. It was__52__. “Son，the one great thing about today is once it__53__，it is already almost tomorrow.” I thought about how__54__it was. Even in my adult life. I still live waiting for what tomorrow may__55__.Now I know that it is already “almost tomorrow.”
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