急,求英语3分钟演讲,神马主题都行,短一些,因为是上课前3到5分钟讲的,有好几个同学讲,不能太长.要有开场白和结尾,

急,求英语3分钟演讲,神马主题都行,短一些,因为是上课前3到5分钟讲的,有好几个同学讲,不能太长.要有开场白和结尾,
有关文化遗产的最好,没有就算了,只要好就行.
明天就要讲了,
越多越好,
至少要给一句英语开场白和结束语啊

1.Television Addiction
　　Television provides us with a wide range of information and entertainment. However, it's a pity that it may also have a bad influence on young minds. For instance, some TV shows have too much violence and crime. These programs may lead youngsters astray.It is easy for students to become addicted to the excitement of these programs and neglect their homework. Parents must, therefore, keep an eye on what their children watch.
　　电视给我们提供广泛的信息和娱乐.不过, 遗憾的是, 它也会对年轻人的思想有不良的影响.举例来说, 有些电视节目有太多的暴力和犯罪.这样的节目可能使年轻人误入歧途.学生很容易沉溺于这些刺激的节目中而忽视了他们的功课.因此, 父母们应该留意孩子所看的电视节目.
2.Man's Best Friend
　　The dog is man's best friend. He can do many things for us. He can protect our homes. He can guide the blind. He is loyal to his master and never asks for a pay raise.
　　The dog has also made many contributions to English. For example, if there were no dogs, how could a husband tell his wife her cooking tastes like dog food? How could the weatherman say, "It's raining cats and dogs?" So the next time a dog lifts a leg to your bicycle, don't kick him. Bend down and say, "Take your time."
　　狗是人类最好的朋友.它可以为我们做许多事情.它可以保护我们的家.它可以引导盲人.它对主人忠实而且从不要求加薪.
　　狗还对英文有许多的贡献.举例来说, 如果没有狗的话, 做丈夫的如何告诉他太太她煮的菜吃起来像狗食?气象播报员又如何能用猫和狗来表示雨下得很大呢?因此下次有狗对你的自行车抬腿撒尿时, 可别踢它.要弯下腰对它说：“慢慢来.”
3.Global Warming
　　Have you noticed that it's getting warmer and warmer every year? To put it simply, that's because of air pollution. Scientists tell us that because of air pollution, the earth's heat cannot escape. This is known as global warming. If this situation is allowed to continue, it will just keep getting hotter and hotter. Then, can you imagine what will happen? We should all, therefore, do our part to stop polluting the air and help save the world.
　　你有没有注意到天气一年比一年变得还要暖和了呢?简言之, 那是因为空气污染的缘故.科学家告诉我们由于空气污染, 地球的热气无法散出去.这就是为人所知的全球变暖.如果我们任由这种情形一直持续下去, 地球就会变得越来越热.那么, 你能想象会发生什么事吗?因此, 我们全都应该尽一己之力来防止污染空气并拯救地球.