趣味实验：将一手帕放在100mL乙醇和75mL水构成的溶液里浸泡，等手帕浸透后拿出来点燃，可以看到明显的火焰，但火焰熄灭后手帕完好无损．

    An officer（军官）is at a bus stop. He wants to see his girlfriend by bus. He wants to tell his girlfriend the time of his bus, and then she can meet him at the stop in her car. He wants to call his girlfriend on a pay phone（付费电话）,but he doesn't have a coin（硬币）for the phone. He wants someone to help him.

    A soldier（士兵）is near the stop. The officer walks to the soldier and asks,“Do you have any coins for the phone?”

    “Let me have a look,” says the soldier. “I'll see if I can help you.”

    “Don't you know how to speak to an officer?” says the officer. “Now let's say it. Do you have any coins for the phone?”

    “No, sir,” says the soldier.