燃烧与我们的生活密切相关，请回答下列问题：（1）请你例举一_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

燃烧与我们的生活密切相关，请回答下列问题：

（1）请你例举一个事例说明物质的燃烧可以造福于人类：______．

（2）火如果使用不当也会给人类带来灾难，请你说说下列灭火事例所根据的原理：①油锅着火用锅盖盖灭______；②森林着火，开辟隔离带______．

（3）一般情况下，CO₂既不燃烧也不支持燃烧，但是点燃的镁带却能在二氧化碳中继续燃烧，生成氧化镁和单质碳，该反应的化学方程式为______．

答案

（1）燃料燃烧放出大量的热，可以为人类提供热量．

（2）①油锅着火用锅盖盖灭是利用了隔绝氧气或空气的原理；②森林着火开辟隔离带的目的是清除或隔离可燃物．

（3）点燃的镁带却能在二氧化碳中继续燃烧，生成氧化镁和单质碳，该反应的化学方程式为：2Mg+CO₂

点燃

.

2MgO+C．

故答案为：（1）提供热量等（其他合理答案亦可）；（2）隔绝空气；清除可燃物；（3）2Mg+CO₂

点燃

.

2MgO+C．

单项选择题

砂石桩桩长不宜小于( )。

A．1m

B．2m

C．3m

D．4m

完形填空

While watching the Olympics the other night,I came across an incredible sight.The　1　was swimming and started with only three men.For one reason or another,two of them had a　2　start,so they were disqualified.That would have been difficult enough,not having anyone to 　3　against.
I watched the man　4　off the blocks and knew immediately that something was wrong.Now I’m not an expert　5　but I do know a good dive　6　a poor one,and this was not exactly medal　7　.I listened to the crowd begin to　8　this poor man who was clearly having a　9　time.Finally he made his turn to start back.It was　10　.He made a few desperate strokes (划水) and you could tell he was exhausted.
But in those few　11　strokes,the crowd had changed.No longer were they laughing,but beginning to　12　.Some even began to　13　things like,“Come on,you can do it！”,and he　14　finished his race.The crowd went　15　.Even though he recorded one of the　16　times in Olympic history,this man gave more heart than any of the other　17　.
In a competition where athletes remove their silver medals,feeling they have　18　been cheated out of gold,or when they act so　19　in front of their competitors,it is nice to watch an underdog (失败者),a man that gave his all—knowing that he had no chance,but competed because of his　20　and the spirit of the games.

C．successfully

B．competitors

B．independence

C．determination