[0:01.064]UNIT 2 第二单元
[0:02.741]DNA
[0:05.221]Lesson 11: 第11课：
[0:06.710]Cloning People? 克隆人?
[0:09.887]What if scientists could make clones of human beings? 如果科学家能够克隆人类会怎么样?
[0:14.388]Each clone would have the same DNA. 每一个克隆人都有着同样的DNA。
[0:17.860]But would they be exactly the same as the original human? 但是他们会和原来的人一模一样吗?
[0:21.818]Or would they be different? 或者他们是不同的?
[0:24.948]Good question! 好问题!
[0:26.578]In some ways, 从某些方面来说，
[0:27.913]clones would be exactly the same. 克隆人会是一模一样的。
[0:30.637]They would be the same height and they would have the same hair colour, for example. 例如，他们一样高，有着同样颜色的头发。
[0:35.905]But each clone would be a different person. 但是，每一个克隆人都是不一样的。
[0:38.716]Why? 为什么?
[0:39.827]Because we are more than our DNA. 因为我们不止受DNA的影响。
[0:42.484]Many things change us: 很多事情可以改变我们：
[0:44.351]the places we live, the food we eat and the people we know. 我们居住的环境，我们吃的食物和我们认识的人。
[0:49.642]Did you know? 你知道吗?
[0:51.391]· We can only make clones from living DNA. · 我们只能用活的DNA来进行克隆。
[0:54.903]After a person or animal has died, 一个人或者动物死后，
[0:58.001]we cannot clone them. 我们就无法克隆了。
[1:00.231]· There are two ways to clone people. · 克隆人类有两种方法。
[1:03.101]We can divide a growing egg in half. 我们可以把一个成长中的胚胎分成两部分。
[1:06.385]Then we would have two eggs with the same DNA. 然后我们就有了两个有着一模一样DNA的胚胎。
[1:10.460]Or we could clone an adult person, the same way scientists cloned Dolly, the sheep. 或者，我们可以克隆一个成年人，用跟克隆多利一样的方法，就是那只克隆羊。
[1:19.036]Would cloning humans be a good or bad thing? 克隆人类是好事，还是坏事?
[1:23.076]· Why would you clone someone? · 为什么要克隆人类呢?
[1:25.119]Some people worry about the answer to that question. 有些人担心那个问题的答案。
[1:28.533]· Other people think human cloning is okay. · 有些人觉得克隆人类是可以的。
[1:31.883]It may let scientists find new ways to help sick people. 它可以帮助科学家找出帮助病人的新方法。
[1:36.674]I think it would be fun to have a twin, 我觉得有一个双胞胎很有意思，
[1:39.188]but I don't think I would want to be cloned! 但是我不想被克隆!
[1:42.990]Changing DNA 改变DNA
[1:45.692]Can they do that? 他们能这样做吗?
[1:47.813]Have you ever seen a pig with a dog's body? 你有没有见过一头长着狗的身体的猪?
[1:50.735]Of course not! 当然没有!
[1:52.259]Pigs and dogs can't have babies. 猪和狗不能生孩子。
[1:54.835]They can't combine their DNA. 它们不能合成它们的DNA。
[1:57.600]But now, scientists can. 但是现在，科学家可以。
[2:00.318]Scientists can take DNA from one kind of animal 科学家们能够从一种动物中提取DNA，
[2:03.947]and put it into another kind of animal. 并把它放进另一种动物体内。
[2:07.011]They can design new plants by combining the DNA of other plants. 他们可以通过合成DNA来研究出新的植物。
[2:12.132]They can even combine the DNA of a plant and an animal. 他们甚至可以将一种植物和一种动物的DNA进行合成。
[2:17.505]What kind of DNA are they wearing? 他们有着什么样的DNA?
[2:20.961]Did you know that scientists have changed the DNA of some cotton plants? 你知道科学家们改变了某种棉花的DNA吗?
[2:25.753]Many clothes are made of cotton. 许多衣服都是用棉花做的。
[2:28.266]Why did scientists change the DNA of cotton plants? 为什么科学家要改变棉花的DNA呢?
[2:31.786]Because insects damage many cotton plants. 因为有些昆虫毁坏了棉花。
[2:34.912]By changing the DNA, scientists made stronger cotton plants. 通过改变DNA，科学家创造了更健壮的棉花。
[2:40.866]What else have scientists designed by changing DNA? 科学家通过改变DNA还研究出了什么?
[2:45.626]· A new kind of corn. · 一种新型玉米。
[2:47.653]Ordinary corn has a problem: insects like to eat it! 一般的玉米有一个问题：遭虫咬!
[2:52.350]But they don't like to eat the new corn. 但它们不喜欢吃新型的玉米。
[2:55.508]· A new kind of rice. · 一种新型水稻。
[2:57.519]Ordinary rice doesn't have Vitamin A. 一般的水稻没有维他命A。
[3:00.771]The new rice does, and it's better for you. 新的水稻有，这对你有好处。
[3:04.368]· Cows that make more milk. · 奶牛产更多的牛奶。
[3:07.573]What's next? 接着是什么?
[3:09.930]Some scientists are worried. 科学家很担心。
[3:12.318]They say we need to know more about DNA before we start changing it. 他们说我们必须在改变它之前，知道更多关于DNA的东西。
[3:17.554]We can make plants that are bad for insects. 我们可以造出对昆虫不利的植物。
[3:20.617]But what if the plants are bad for humans, too? 但是如果这些植物对人类也有害呢?
[3:23.728]Humans are us! 人类就是我们!
[3:25.283]People! 人类!
[3:26.597]LET'S DO IT! 做一做
[3:28.157]A debate is an argument between two groups. 辩论是两个组之间的争辩。
[3:33.036]One group argues for an idea; 一组为一个观点争辩;
[3:36.070]the other argues against it. 另一组反对那个观点。
[3:39.077]Plan a debate about this topic: 准备一个关于这个话题的辩论：
[3:42.283]is it a good idea to change the DNA of the food we eat? 改变我们吃的食物的DNA是一个好主意吗?
[3:48.506]Some people say doing this makes our food better. 一些人说这样做会使我们的食物更好.
[3:52.771]Others think it is too dangerous. 其他人认为这太危险了。
[3:55.962]Search the Internet for information to help your argument! 从网上查找资料帮助你辩论。
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